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DIAMONDS 



AND 



PRECIOUS STONES. 






DIAMONDS 

AND 

PRECIOUS STONES, 

A POPULAR ACCOUNT OF GEMS. 



CONTAINING 

THEIR HISTORY, THEIR DISTINCTIVE PROPERTIES, AND A 

DESCRIPTION OF THE MOST FAMOUS GEMS; 

GEM CUTTING AND ENGRAVING, AND THE ARTIFICIAL PRODUCTION 

OF REAL AND OF COUNTERFEIT GEMS. 



TRANSLATED FROM THE FRENCH OF 

, LOUIS PIEULAFAIT, 

^ Professor of Physics, Doctor of Sciences. 

By FANCHON SANFORD. 



ILLUSTRATED BY 126 ENGRAVINGS ON WOOD. 



NEW YORK: /\ 
SCRIBNER, ARMSTRONG, AND COMPANY. 
1874. 



Entered, according to Act of Congress, in the year 1873, by 

SCRIBXER, ARMSTRONG, AND COMPANY. 
lu the Office of the Librarian of Congress, af Washington. 



RirSRSIDE, cambripoe: 

STEREOTTPED AKD PRINTED BT 
H. 0. HOUGHTON AND COMPANY. 



^,()3- 



^ 



PREFACE. 



It would be easy for any one who had sufficiently pre- 
pared himself by previous study to write a purely scientific 
work on the subject of precious stones; but this is not 
the intention of the present writer, who aims at interesting 
a wider class of readers than a work of the kind indicated 
would reach. 

In addition to the strictly scientific information to be 
given regarding precious stones, there are connected with 
them a great many facts not less interesting, and equally 
important for the public to know. To these we have 
devoted several sections of the following work. 

In our times precious stones are used almost ex- 
clusively for the purpose of ornament, but in former 
times the case was very different. By reference to the 
authors of antiquity, as well as to those of the middle 
ages and the Renaissance, we have shown the important 
part that they then played, and what ideas prevailed 
regarding them. 

From the thousands of fables and superstitions of 
which precious stones have been the subject, we have 
selected a certain number. In doing so we have dis- 
regarded those calculated only to interest the curious, 



IV PREFACE. 

and have chosen such as were likely to instruct and 
enlighten. 

In Parts iv. and v. it was necessary to introduce some 
of the elements of crystallography, without which those 
two important chapters would have lost a great part of 
their value. We have treated the subject, however, as 
briefly as possible, but, at the same time, in a strictly 
scientific manner. To attempt to popularize science, by 
stripping it, as is so often done, of that which constitutes 
its very essence, is not to popularize, but to disfigure and 
travesty it. 

The part devoted to counterfeit precious stones will 
not be one of the least useful. The facts which it con- 
tains will carry their own teaching with them, and of 
this the purchasers of precious stones will know how 
to avail themselves. 

In another part the methods are explained, by means 
of which modern savants have succeeded in producing 
the majority of the precious stones. These methods, 
and the remarkable results obtained by the employment 
of them, have hitherto remained locked up in collections 
of scientific papers, or in special treatises. We are glad 
to have had the opportunity of first making them known 
to the public at large. 

The illustrations interspersed through the book all re- 
produce as accurately as possible by engraving the ob- 
jects they profess to represent, and none of them are 
fancy sketches. The utmost care has been bestowed on 
this department; for, if the engraver's art is one of the 



PREFACE. V 

most powerful means of spreading knowledge, it can only 
be so by the exact reproduction of nature. 

Lastly, we have constantly endeavoured to arrange 
facts according to their natural relations, so as, by the 
mere exposition, to exhibit, in a succinct form, a notable 
stage in the development of the human mind, both from 
an intellectual and a scientific point of view. 

LOUIS DIEULAFAIT. 



CONTENTS. 



PART I. 

PAGE 

Precious Stones : their origin ; geological position ; 
physical characteristics ; optical and electrical proper- 
ties ; external characteristics ; susceptibility to the 
action of light and heat, I 

PART II. 

Historical Survey of Precious Stones. — Ideas entertained 
by the ancients, and in the middle ages, concerning 
the nature and properties of precious stones. — Their 
classification based upon the analysis of modern 
chemistry, 31 

PART III. 
The Diamond, 53 

PART IV. 

Sapphire. — Ruby. — Balas Ruby, — Spinel Ruby.— Topaz. 
— Emerald. — Beryl. — Aquamarine. — Cymophane. — 
Turquoise, no 

PART V. 

Quartz.— Occidental Topaz. — Smoky Topaz, or Alengon 
Diamond. — Water Sapphire. — False Emerald. — Bohe- 
mian or Brazilian Ruby. — Hyacinth of Compostella. — 
Iris. — Aventurine. — Opal. — Hydrophane. — Agate. — 
Chalcedony. — Chrysoprase. — Cacholong. — Heliotrope. 



Vlll CONTENTS. 

PAGE 

—Onyx. — Sard. — Sardonyx. — Sardoine. — Sardagate. 
— ^Jasper. — Zircon. — Garnets. — Peridote. — Olivine. — 
Jade. — Tourmaline. — Lapis-lazuli. — Malachite. — He- 
matite, 146 

PART VI. 
PearL — Coral — Amber. — ^Jet, 186 

PART VII. 

Artificial Production of the Diamond. — Boron Diamond 
— Cagniard de Latour — Gannal — MM. Despretz and 
de Chancourtois, 208 

PART VIII. 

Artificial Production of Real Precious Stones. — Results 
obtained. — Becquerel. — Ebelman. — Gaudin. — H enri 
Sainte-Claire Deville. — De Sdnarmont. — Daubrde. — 
Durocher. — Sainte-Claire Deville and Caron, &c., . . 222 

PART IX. 
False Precious Stones, 233 

PART X. 
Cutting. — Setting. — Engraving of Precious Stones, . .252 



Table of General Characteristics of Precious 
Stones, 290 



LIST OF THE ILLUSTRATIONS. 



FIG. PAGE 

1. Igneous Rocks — The Volcano of Jorallo in Mexico, . . 3 

2. Igneous Rocks — Horizontal Columnar Basalt at St. 

Helena, 7 

3. Structure of Sedimentary Rocks, 8 

4. Trilobites, . 9 

5. • Lyell's Cephalaspis, 9 

6. Calamite, 9 

6'^- Lepidodendron 9 

7. Fossil Dragon-fly, 10 

8. Turrilites catenata, ll 

9. Terebratula, ll 

10. Mammillary Ammonite, II 

11. Cerithium thiara 12 

12. Gigantic Cerithium, 12 

13. Cancellaria cancellata 12 

14. The Great Palseotherium, 13 

15. The Common Anoplotherium, 14 

16. Course of a luminous ray in a homogeneous medium, . 20 

17. Double refraction of Iceland spar, 21 

18. Aspect of a candle seen through a doubly refractive 

crystal, 23 

19. Egyptian Scarabaeus cut in hard stone, 32 

20. 21. Egyptian iigures carved in hard stone 34 

22. Cornelian engraved : Egyptian, . 35 

23. Egyptian Ring of Cornelian, 35 

24. 25. Egyptian Rings and Tablets engraved on both sides, 36 

26. View in a Diamond District of Brazil, 59 

27. Size of a Diamond hidden by a slave in the corner of 

his eye, 61 

28. First wash of the Diamond-yielding Soil in Brazil, . . 63 



X LIST OF THE ILLUSTRATIONS. 

FIG. PAGE 

29. Dimensions of a Brilliant of 10 carats, 74 

30. Maillard's Experiment, 78 

31. Combustion of the Diamond by Lavoisier, 81 

32. 33. Combustion of the Diamond in Oxygen, ... 82, 83 

34. Diamond of the Rajah of Mattan, 85 

35. The Nizam Diamond, 86 

36. The Regent or Pitt Diamond, 87 

37. Empress Eugenie Diamond, 89 

38. The Sancy Diamond, 90 

39. Star of the South Diamond before and after cutting, . . 93 

40. The Koh-i-noor Diamond before re-cutting, .... 95 

41. The Koh-i-noor Diamond after being re-cut, .... 98 

42. The Pigott Diamond, 99 

43. The Nassac Diamond, 99 

44. The Orlow Diamond, roo 

45. Surface of Rose-cut Diamonds compared with their 

Weight, loi 

46. The Shah Diamond, 103 

47. Tlie Polar Star Diamond, 104 

48. The Grand-duke of Tuscany Diamond, 104 

49. The Pasha of Egypt Diamond, 105 

50. The Blue Diamond of Mr. Hope, 106 

51. Surfaces of Brilliants compared with their Weight, . . 107 

52. Primitive Form of Corundum, 113 

53. Most common Form of the Corundum, ...... 113 

54. King of Persia's Ruby, 119 

55. Ruby of the King of Visapur, ......... 120 

56. Indian Ruby, from Tavern ier, 120 

57. View of the Mountain of Expilly, Central France, . . 125 

58. Type of Crystal of Topaz, 129 

59. Saxon Topaz, 129 

60. Brazilian Topaz, 129 

61. Siberian Topaz, 130 

62. Topaz of the Grand Mogul, 130 

63. Amethyst engraved — Antonia, wife of Drusus, . . . 132 

64. Fundamental Form of Emerald Crystals, 134 

65. Very common Form of Emerald Crystals, 134 

66. Aquamarine engraved— Julia, daughter of Titus, . . . 139 

67. Primitive Form of Quartz, 148 

68. Most ordinary Form of Quartz Crystals, 148 



LIST OF THE ILLUSTRATIONS. XI 

rlG. PAGE 

69, 70. Modified Crystals of Quartz, 149 

71. Dodecahedral Quartz, 150 

72. The Great Geyser (Opals and Chalcedonies), . . . . 158 

73. Opal of D'Augny, 161 

74. Agate engraved — Alexander the Great, 169 

75. Chalcedony — Cameo of Hyllus, 1 70 

76. Cornelian engraved — Seal of Michael Angelo, . . . . 170 

77. The Zircon, 172 

78. Slodified Zircon 172 

79. Zircon from the Cabinet of M. Dree, 172 

80. Garnet, Rhomboidal type, 1 74 

81. Garnet, Trapezohedral type 174 

82. Common Form of Tourmaline, . l8i 

83. Sardonyx engraved — Marriage of Cupid and Psyche. . 187 

84. Arrangement of Layers of Peai-], 190 

85. Arrangement of Layers of Mother-of-pearl, 190 

86. Polypes of Coral in different degrees of development, . 200 

87. Lizard imprisoned in a fragment of Amber, .... 205 

88. Gannal's arrangement for the Production of the Diamond, 215 

89. M. Despretz's arrangement for the Production of the 

Diamond, 21 7 

90. Voltaic Apparatus of M. Becquerel for the Production of 

Crystals, 226 

91. Egyptian Bracelet in Ceramic Paste, vi^ith coloured orna- 

mentation, 239 

92. Egyptian Vase of Blue Glass, with white and yellow 

ornaments, 240 

93. Egyptian Moulding in Ceramic Paste, 241 

94. Egyptian Ring, with a Bezel of Ceramic Paste, . . . 241 

95. Egyptian Ring of Gold, with inlaid work of Enamel, . 242 

96. Egyptian Moulding in Ceramic Paste, 243 

97. View of Coster's Diamond Works at Amsterdam, . . 255 

98. Cubic System, 257 

99. Regular Octahedron, 257 

100, loi. Common Forms of the Diamond, ... . . . 257 

102. Flat Diamond of the Grand Mogul, , 258 

103. Natural Octahedral Diamond, 259 

104. Transitionary Form of the Diamond in arriving at the 

Form of the Brilliant, 259 

105. Do. do 259 



Xll LIST OF THE ILLUSTRATIONS. 

FIG. ^ PAGE 

1 06. Brilliant, seen sidewise, * . . . 260 

107. Brilliant, seen from above, 260 

108. Semi-brilliant, 261 

109. Holland Rose, 262 

no. Pendeloque of Ta vernier, 263 

111. The Star invented by Caire, 264 

112. Room in which the Diamond-splitters work in Coster's 

Establishment, Amsterdam, 265 

113. Details of a Compartment of the Splitter's Workroom, . 267 

114. The Splitter 268 

115. Table of the Splitter, 270 

116. The Cutter, , 271 

117. Diamond-cutter's Table, 272 

118. General View of the Polishing-room, 274 

119. The Polisher, 276 

120. Instruments used in Polishing, 277 

121. Cutting of Precious Stones other than the Diamond, . . 280 

122. Forms in which Stones are often cut, 281 

123. The Lathe at work, 283 

124. Tools and other objects used by the Engraver of Hard 

Stones, 285 

125. Apparatus for sawing Hard Stones, 287 



DIAMONDS 



PRECIOUS STONES. 



PART I. 



Precious Stones.- their Origin; Geological Position: Physical 
Characteristics ; Optical and Electrical Prope7'ties ; External 
Characteristics ; Susceptibility to the action of Light and Heat. 



' The jewel that we see, we stoop and raise; 
But that we do not see, we tread upon, 
And never think of it." 



In the following pages we intend to treat not 
merely of precious stones strictly so called — that is, 
such mineral substances as have in all times at- 
tracted the attention of man by their hardness, 
their brilliancy, their colour, their scarcity, &c., but 
also of a certain number of productions which have 
nothing in common with the true precious stones, 
either in composition or origin, but which as articles 
of finery and adornment play precisely the same 
part as the latter. 

When we contemplate the boundless wealth of 

nature we might imagine that the number of precious 

1 



\^ 



2 PRECIOUS STONES. 

stones would be unlimited; but this, as we shall 
see, is far from being the case. We must remark, 
however, that it is impossible to draw a hard and 
fast line between the most common precious stones 
and ordinary stones, since we have here a particular 
case of the grand law formulated more than a 
century ago by the illustrious Linnaeus: Natura 
nonfacit saltus — " Nature never makes a leap." 

ORIGIN OF PRECIOUS STONES. 

All precious stones are transparent, or at least 
translucent, from which it may be concluded that 
the matter of which each consists is homogeneous. 
Now this homogeneity could never have been 
attained by the mixture of their elements in the 
solid state, however finely these may have been 
pulverized, and hence they must have been in the 
condition of either gases or liquids. Nature has a 
multitude of means by which these transformations 
of matter are effected, all referable to three general 
processes : — 

1st. Direct fusion of the substance by the action 
solely of heat. 

2d. Dissolution of the substance by the aid of 
foreign substances at variable temperatures. 

3d. Bringing together, in the state of vapours, sub- 
stances destined to become the elements of the stone. 







*^«V^-' -"Til/SB! 



ORIGIN OF PRECIOUS STONES. 5 

From the point of view of their formation, there- 
fore, precious stones may be naturally divided into 
two classes. 

The first comprehends stones produced by direct 
fusion, by crystallization in an excess of their 
meked substance, by volatilization of their elements ; 
in a word, by the direct intervention of heat. 

The second includes stones which have been 
formed in the midst of a solution of which water 
has been generally one of the constituent elements. 

Hence some precious stones are met with in those 
portions of our globe which have been subjected 
to a high temperature, while others are found in 
those that have never supported such a temperature, 
or what comes to the same thing, that have been 
perfectly cooled at the period when they furnished 
to the water the elements of the stones of which we 
are speaking. 

It is therefore of some importance to distinguish 
those portions of our globe which have been sub- 
jected to the action of fire from those that have not; 
and this is easily done. 

GEOLOGICAL POSITION. 

When we consider the solid part of our globe 
we recognize immediately its division into earth, — ■ 
using that word in its agricultural sense ; and stones 



6 PRECIOUS STONES. 

— more or less detached, or in the state of continu- 
ous rocks. The least examination shows further, 
that this earth itself is composed to a great extent 
of stones gradually decreasing in size ; so that we 
easily arrive at the well-established conclusion that 
the earth and the stones have the same origin. 

If then, in thought, we remove from the surface 
of the land the earth, whose thickness indeed is 
very inconsiderable, we perceive that the solid part 
of our globe consists exclusively of rocks. 

These rocks are divided into two great classes: 
one formed of melted materials, like the lavas of 
our modern volcanoes; the other produced by seas, 
rivers, and lakes of ancient periods, in the same 
manner as we see deposits accumulated by the 
waters in our own time! The first are called igne- 
ous rocks ; the second, sedimentary. 

The Igneous Rocks, pushed from the interior of 
the earth in a plastic state, lift themselves above 
the surface of the soil in irregular shapes, in pre- 
cipitous peaks, or vast cones, and sometimes in 
those basaltic columns whose aspect is so striking 
and impressive. 

The accompanying cut exhibits a good example 
of these basaltic rocks, but we may remark that 
columnar basalt is comparatively rare, and that 
igneous rocks in general possess no regularity of 
structure. Very frequently they are intersected by 



GEOLOGICAL POSITION. 



cracks in all directions — a feature produced by the 
contraction resulting froom cooling. 

The Sedimentary Rocks present an aspect so 




Fig. 2.- — Horizontal Columnar Basalt at St. Helena. 



completely different from that of igneous forma- 
tions, that they may be recognized at a great dis- 
tance, even by inexperienced eyes. Being deposited 
in water in parallel layers, they have preserved the 
same disposition after being left dry. Sometimes, 
indeed, the horizontal layers have been singularly 
displaced from their original direction : sudden 
changes and movements of the soil have tilted them 
up and contorted them ; but still the parallelism of 



8 



PRECIOUS STONES. 



the strata, and their disposition by successive layers, 
is nearly always clearly discernible. Fig. 3 is an 




Fig. 3. — Structure of Sedimentary Rocks. 

example of sedimentary rock, and it shows very 
distinctly the regularity of structure which these 
rocks usually display. 

Beyond this general distinction there is another, 



GEOLOGICAL POSITION. 



less prominent perhaps, but quite as definitely 
marked. The remains of myriads of animals and 





Fig. 5. — Lyell's Cephalaspis. 



Fig. 4. — Trilobites. 
a, Paiadoxides bohemicus. b, Phacops latifrons. 



plants have been left age after age in the sediments 
of the different eras ; these remains are known as 
Fossils. They reveal forms of life very different 





Fig. 6.— Calamite. Fig. 6".— Lepidodendron of the Coal Formation. 

from those that exist in the present condition of our 
globe ; and their dominant races, long since extinct, 



lO PRECIOUS STONES. 

have furnished names for remote eras, — for all the 
geological ages, indeed, included between the azoic 
age and the age of man. 

With the high temperature of the igneous forma- 
tions, life was incompatible; consequently no fossil 




Fig. 7. — Fossil Di ^ ^ _ ; Secondary Epoch. 

ever appears, or possibly could appear, in rocks of 
this kind. In sedimentary formations, on the con- 
trary, such remains abound, and furnish another 
excellent means of distinguishing them from the 
igneous rocks. 

A few illustrations will exemplify types of animal 
and vegetable fossils incident to different periods. 



GEOLOGICAL POSITION. 



II 



Figs. 4, 5, and 6 represent animal and vegetable 
forms that existed in a period incalculably remote, 




Fig. 8. — Turrilites catenata. 




Fig. g. — Terebratula. 




Fig. 10. — Mammillary Ammonite. 



and are found in rocks belonging to what has been 
called the primary or palaeozoic period. 

Those represented by Figs, y, 8, 9, and 10 ap- 
pertain to the secondary formations, such as the 



12 



PRECIOUS STONES. 



oolite or Jurassic formation, named from the Jura 
Mountains, in whose rocks such specimens are 




Fig. II. — Cerithium 
thiara. 





Fig. 13. — Cancellaria 
cancellata. 



Fig. 12. — Gigantic Cerithium. 



found ; and the cretaceous period, or period of the 
chalk, next in order of time. 

To the cretaceous period succeeded the tertiary 



GEOLOGICAL POSITION. 1 3 

formation, in which are found such shells as those 
represented by Figs, ii, 12, and 13. By this time 
creatures had begun to appear bearing a strong 




Fig. 14. — The Great Palaeotherium. 

resemblance to those of the present period. Figs. 
14 and 15 illustrate characteristic types. 

After the tertiary formation comes the post-ter- 
tiary or quarternary formation, in which the animals 
are quite analogous to those of our own period. 

If we inquire of chemistry what is the composi- 



14 PRECIOUS STONES. 

tion of the two grand classes of rocks above-men- 
tioned, we obtain this simple answer: — The calcare- 
ous element predominates in all sedimentary for- 
mations (excepting the most ancient) ; silicious and 
aluminous elements in igneous formations. 




Fig. 15. — The Common Anoplotherium. 

Consequently, stratification, presence and often 
extreme abundance of fossils, great prepondera7ice of 
the calcareous element, are the unmistakable char- 
acteristics of sedimentary formations. Absence of 
stratification, complete absence of fossils, great pre- 
ponderance of the silicious and aluminous elements, 
are the characteristics of igneous formations. 

Now if we investigate the chemical composition of 
precious stones, we shall find that the greater num- 
ber of those which really merit this appellation, are 



GEOLOGICAL POSITION. 1 5 

principally formed of silica and alumina, or of one 
of these two substances. It follows, then, that 
precious stones should be found most frequently in 
igneous formations, or in the debris of such forma- 
tions: and we naturally conclude that they will 
be most abundant in countries where the geological 
development is chiefly of this kind. Theoretically 
this is true ; but practically the finding of precious 
stones depends far more upon the condition than 
upon the abundance of the igneous rocks. These 
eagerly sought treasures are only the very rare ex- 
ceptions in enormous masses of rock, and the latter 
must be broken up into small fragments before their 
riches can appear. 

We know that under the influence of atmospheric 
agencies the most obdurate rock is gradually dis- 
integrated ; but atmospheric action has feebly con- 
tributed to the production of sands and the for- 
mation of arable lands. In different periods of its 
existence our globe has experienced agitations of 
extreme violence, the principal effects of which, 
after the lapse of countless centuries, are at this day 
perfectly discernible. 

The last of these grand commotions belongs to 
the period which geologists have named the quar- 
ternary, an epoch relatively not far removed from 
our own. 

Floods of water at that time spread across the 



1 6 PRECIOUS STONES. 

continents; mountains of ice, of which the Alpine 
glaciers are but meagre vestiges, invaded even the 
most temperate zones; streams of irresistible violence 
— such as the great rivers of our day can scarcely 
give us any idea of — furrowed the earth. Under 
the influence of these agencies, the stupendous 
forces of which were all working in one direction, 
the grinding down and destruction of the rocks was 
effected over vast spaces, and to considerable depths. 
Now it is precisely in the ddbris of igneous rocks, 
whose reduction to sand was accomplished during 
this period, that the greater number of precious 
stones are found ; and above all, the diamond. 

But although the diamond-producing soils are 
comparatively modern alluvial formations, it must 
not be concluded that the diamond, and the other 
precious stones which accompany it, are of recent 
origin. In reality, that which is recent is the reduc- 
tion of the rocks to the alluvial state ; but the rocks 
themselves, and consequently the precious stones 
that they contain, are often extremely ancient. 
There are precious stones whose existence was 
anterior to the first sedimentary formations ; they 
had their place in the world long before the plants 
and animals began their measureless succession; 
and they are an inheritance to man from the azoic 
age, when as yet no foreshadowing of his existence 
had fallen upon the globe. 



PHYSICAL CHARACTERISTICS. 17 

PHYSICAL CHARACTERISTICS OF PRECIOUS 
STONES. 

WEIGHT AND MOLECULAR ACTION. 

Specific gravity. — Every one knows that two 
equal volumes of different substances have seldom 
the same weight: a piece of lead, for instance, is 
much heavier than a piece of wood exactly equal to 
it in size. If we find the weight of a substance, and 
also that of an equal volume of another substance, 
selected as a term of comparison (distilled water is 
the term that has been chosen), and if we divide the 
weight of the first body by that of the second, we 
obtain a number which expresses how many times, 
and fractions of times, the body considered is more 
or less heavy than that to which it is compared. 
The number thus obtained is its specific gravity. 

In the case of precious stones it is a characteristic 
of extreme importance, for it is frequently the means 
by which the difference is detected between stones 
that the eye might easily confound. In this way, 
for example, the diamond can be at once distin- 
guished from the zircon, the specific gravity of the 
former being 3*4, and that of the latter 4"4. 

Hardness. — We should be careful not to fall into 

the very frequent error of confounding the quality 

of hardness with that of resistance to crushing or 

2 



1 8 PRECIOUS STONES. 

concussion. There are minerals that may be crum- 
bled between the fingers, and that are yet none the 
less hard. The hardness of a substance, according 
to the definition of Delafosse, is "the resistance 
which it opposes to the action of a point like that 
of a steel needle which may be drawn across it, or 
to the angular part of another mineral passed with 
friction over its surface." 

Hardness is an indispensable quality of gems. 
If a stone were not very hard, the continual friction 
to which it is subjected would very soon destroy its 
polish ; and with the polish, transparency, brilliancy, 
fire — all that constitutes its value — would vanish. 

It is owing to this quality of hardness, added to 
the unchangable nature of their substance, that 
stones, cut perfectly by Egyptian artists thousands 
of years ago, have reached us intact; and give us the 
most interesting proof of the progress in arts and 
civilization which had been attained in those remote 
periods. 

Fusibility. — Fusibility is the property which solid 
bodies possess of passing into the liquid state, when 
they are subjected to a sufficient temperature. 

For precious stones in particular the point of 
fusion is lower in proportion as the composition of 
the stone is more complex. Thus the diamond, a 
simple body, is absolutely infusible. The ruby, the 
sapphire, the topaz, binary bodies, can only be 



OPTICAL PROPERTIES. I9 

melted before the oxyhydrogen blowpipe. The 
simple silicates, ternary bodies, are fusible at a much 
lower temperature ; and the multiple silicates offer 
no serious resistance. 

The temperature of fusion of precious stones, 
since it is allied in a remarkable manner with their 
hardness, serves as a good characteristic for distin- 
guishing them. 

OPTICAL PROPERTIES. 

Refraction. — When a luminous ray passes through 
a homogeneous medium, its course is in a straight 
line, as shown in Fig. 16, a phenomenon with which 
everyone is familiar. But when it passes from one 
medium into another, the case is generally different, 
and the ray suffers a remarkable modification. It 
is then more or less diverted from its primitive 
direction, and has the appearance of being broken, 
whence the phenomenon has been termed refraction. 
A stick plunged into water will exemplify this 
effect. 

The extent to which the luminous rays are 
diverted in traversing transparent bodies varies 
greatly. This variation is generally connected with 
differences in the nature and composition of the re- 
fracting bodies; but it is likewise intimately con- 
nected, as experiments prove, with the molecular 



20 



PRECIOUS STONES. 



constitution of these bodies. For example, Iceland 
spar and aragonite, whose chemical composition 
is identical, both consisting of pure carbonate of 
lime, refract the light unequally, for the sole reason 
that their molecular constitution is very different. 




Fig. i6. — Course of a luminous ray in a homogeneous medium. 

Double Refraction. — Among diaphanous bodies 
there is a numerous class of substances that possess 
the curious quality of presenting two images of one 
object. If a crystal of Iceland spar is placed upon 
a piece of white paper bearing an inscription, as in 
Fig. 17, two images will be visible of every point. 



OPTICAL PROPERTIES. 21 

and both images will show deviation. This is an 
instance of what is called double refraction. 

When a body, crystallized or not, is perfectly 
homogeneous in all its parts, so that its elements 
are disposed everywhere in a uniform manner, one 
can-easily understand that the light must traverse 
it regularly, and must present a single image of 
every object: such bodies possess the property of 
simple refractio7i. 




Fig. 17. — Double refraction of Iceland spar. 

Crystals belonging to the monometric or tesseral 
system, as the cube or octahedron, since their mole- 
cular disposition is perfectly regular, never exhibit 
the phenomenon of double refraction, in whatever 
direction they are traversed by the light; but crys- 
tals of all other systems possess the power of 
double refraction, differing in its effects as the crystal 
appertains to a system more or less closely related 
to the regular system. 

As all precious stones that are highly valued are 



22 PRECIOUS STONES. 

crystallized, and it has been well ascertained what 
stones display simple and what stones double refrac- 
tion, it sometimes becomes a matter of importance 
to know whether a given stone is really doubly- 
refrangent, in order to distinguish it from one which 
possesses simple refraction, but to which in other 
respects it is quite similar in appearance. As 
precious stones are all small, a special method of 
procedure is here necessary in order to obtain the 
phenomenon of double refraction. 

Take, for example, a small stone, cut in form of a: 
brilliant, concerning whose nature there is some 
doubt. 

Place the stone at a level with the eye, holding it 
in one hand; in the other hand take an object of 
small dimensions, a pih for instance, and move it 
slowly on the other side of the stone until the 
eye is able to perceive it. If the stone is doubly- 
refractive, the rays will bifurcate on entering it, and 
accordingly two images of the pin will be seen, if it 
is not held too near the stone. If it is held very 
near the stone, the rays will not be far enough 
apart at the point where they emerge into the air 
to allow their separation to be evident. 

If the experiment is made at night, instead of a 
pin a lighted candle may be used, the candle being 
placed beyond the reach of currents of air, so that 
its flame may be pure and regular. The pheno- 



OPTICAL PROPERTIES. 23 

menon will be exactly the same, and have the aspect 
presented by Fig, 18. 

If the phenomenon of double refraction is pro- 
duced, the conclusion may be made without hesita- 
tion that the stone tested is not a diamond ; for the 
diagpond, since it appertains to the cubic (mono- 




Fig. 18. — ^Aspect of a candle seen through a doubly-refractive crystal. 

metric) system, possesses simple refraction. The 
stone experimented on, therefore, is no doubt one 
of those with which the diamond is sometimes con- 
founded, such as the sapphire and the zircon, which 
possess double refraction. 

Polarization. — It is well known that if a beam of 
light falls upon a plane and polished surface it is re- 



24 PRECIOUS STONES. 

fleeted ; but it is not so well known that if to this 
ray, which has already been reflected at a certain 
angle, a second mirror with plane inclined is pre- 
sented, there are certain positions in which the ray 
will be no longer reflected by the second mirror. 
The light has acquired by its first reflection a pro- 
found modification, which is designated by the name 
oi polarization by reflectio7i. 

In traversing certain crystals the light is sub- 
jected to the same changes; that is to say, the rays 
emerging from the crystal are no longer reflected 
when they fall at a certain angle upon a plane 
mirror ; and they have become completely powerless 
to traverse certain crystals, otherwise perfectly trans- 
lucid, when the latter are presented to them accord- 
ing to a determinate direction. The phenomenon 
thus presented is polarization by refraction. 

Double refraction and polarization are qualities 
of crystals which are most intimately connected ; 
and the combinations of these two manifestations 
produce magnificent phenomena of colouring, un- 
attainable by substances producing simple refraction. 
It is very easy, by aid of a polariscope, to be assured 
upon the instant whether a precious stone possesses 
or not the power of double refraction. 

Dichroism, polychroism, asteria. — The pheno- 
mena designated by these expressions, and which 
give a magical beauty to certain precious stones. 



ELECTRICAL PROPERTIES. 2$ 

are entirely due to the refraction and polarization 
of light. They show that the substances in which 
they are produced have not identically the same 
constitution in all their parts. 

ELECTRICAL PROPERTIES. 

In a general manner, all bodies acquire electricity 
by friction; only, one kind keep for a longer or 
shorter time the electricity confined as it were in 
their pores, while the other kind lose it instantly. 
The first are isolating bodies, the others are conduct- 
ing bodies. 

Precious stones belong to the first of these cate- 
gories ; but they exhibit great difference in the time 
during which they remain electrified; and this 
characteristic affords, in experienced hands, a very 
useful test for distinguishing one from another. 

There are certain precious stones which possess 
the curious quality of becoming electric when they 
are subjected to heat. The tourmaline is especially 
susceptible to this thermotic electricity. 

When precious stones are rubbed with the same 
material, usually a bit of cloth, some of them acquire 
positive electricity and the others negative electri- 
city. Tourmaline, and other substances electrified 
by heat, usually exhibit positive electricity at one 
extremity and negative at the other. 



26 PRECIOUS STONES. 



OUTWARD CHARACTERISTICS. 

TRANSPARENCY. 

Transparency is the property that precious stones 
possess of being more or less easily traversed by 
luminous rays. 

They are transparent when, being interposed be- 
tween the eye and an object, they allow all the out- 
lines of this object to be seen with perfect clearness. 
Example: the diamond. 

They are semi-transparent -wh^n the objects viewed 
through them are a little confused. Example: the 
emerald. 

They are translucid when nothing can be per- 
ceived when they are placed before the eye, but 
that the light evidently has a passage through them. 
Example: the chalcedony. 

Finally, they are opaque when not a ray of light 
can penetrate them. Example : the jasper. 

LUSTRE. 

" Among minerals great differences are met with 
as regards the manner in which the light acts upon 
their surface. In this respect there are two separate 
effects to be distinguished, lustre and colour, which 
are one to the other as timbre is to sound in a 



OUTWARD CHARACTERISTICS. 2/ 

musical instrument. Colour depends upon the 
nature of the reflected rays, lustre upon their inten- 
sity, and upon certain particular modifications of 
their tint which cannot be defined ; it depends upon 
the structure of the body, its kind of texture, and 
the "greater or less polish of its surface. Lustre, 
like colour and transparency, is susceptible of gra- 
dation ; it is more or less vivid, more or less dull ; 
and disappears entirely in varieties in which the as- 
pect is rough, stony, or earthy " (Delafosse). 

Adamantine lustre. — Intermediate between me- 
tallic lustre and vitreous lustre ; it belongs to cer- 
tain crystals; to the zircon, and above all to the 
diamond. 

Nacreous or pearly lustre. — A mixture of silvery 
and vitreous lustre, resembling, as its name indicates, 
the nacre of pearl. Certain varieties of corundum 
possess this lustre in a very pronounced manner. 

Silky lustre. — Due to straight fibres disposed 
very closely and of equal thickness. It resembles 
the sheen of certain fabrics of mohair. 

Oily lustre. — The stones which possess this lustre 
are generally vitreous stones, which always seem, 
even when newly fractured, to have been impreg- 
nated with oil. 

Resinous lustre. — A medium between the oily 
and the vitreous lustre. The opal generally presents 
this aspect. 



28 PRECIOUS STONES. 

Vitreous lustre. — This lustre recalls exactly the 
fracture of glass. It belongs generally to bodies in 
which the refracting power is inconsiderable. 



ACTION OF LIGHT AND HEAT UPON PRECIOUS 
STONES. 

Light. — When the most valuable precious stones, 
and the diamond particularly, are exposed for a 
certain time to the rays of the sun, and are then 
taken into darkness, they remain luminous, and ex- 
hibit the phenomenon of phosphorescence. This 
curious effect lasts for some time, but gradually 
becomes fainter and fainter, and finally dis- 
appears. 

Heat. — The effects produced upon precious stones 
by heat are even more remarkable than those due 
to the action of light. Heat acts upon them in two 
very dissimilar ways. It modifies the elementary 
constitution of the stone by separating its molecules, 
but this in a manner altogether mechanical; or it 
produces in the stone a veritable chemical reaction. 
In the first case the modifications are temporary, 
and at length the objects return to their primitive 
condition ; in the second case the effects produced 
are permanent. 

As an example of the latter case, we may cite a 
practice whose origin is lost in antiquity, and which 



ACTION OF LIGHT AND HEAT. 29 

is still resorted to daily by lapidaries. It consists 
in submitting a coloured stone (diamond, topaz, &c.) 
to a temperature more or less elevated. Nearly 
always in these conditions the stone changes colour 
permanently. 

A remarkable communication made to the 
Academy of Sciences will serve as an example 
of the first case. 

" MM. Halphen have the honour to present to the 
Academy a diamond of the weight of 4 grammes 
(about 20 carats), presenting a phenomenon which 
has never been before observed, at least to their 
knowledge. 

"This stone is, in its normal state, of a white 
colour, faintly tinged with brown. When it is sub- 
jected to the action of fire, it acquires a very clear 
rose-tint, which it retains for eight or ten days, and 
which it loses gradually, to return to its primitive 
normal colour. 

"This change and return to the primitive state 
may be repeated indefinitely, for the diamond sub- 
mitted to the Academy has been subjected five 
times to this test. 

"The phenomenon in question arrested at first 
the attention of an observer, who was trying at 
random upon this diamond the prolonged action of 
fire. Experiments made since upon other diamonds 
have not produced the same result. 



30 PRECIOUS STONES. 

" This question of colouring diamonds has an im- 
portance which the Academy will easily appreciate, 
when it considers that the stone presented at this 
moment has, in its normal state, a value of 60,000 
francs, while its price in the rose-coloured state, if 
the colour were permanent, would be from 150,000 
to 200,000 francs." 



PART II. 



Historical Suii'ey of Precious Stones. Ideas entertaifted by the 
Ancients, and in the medictval age, concerning the Nature and 
Properties of Precious Stones. Their Classification based upon 
the analysis of Modern Chemistry. 



"Though the same sun with all-diffusive rays 
Blush in the rose, and in the diamond blaze. 
We prize the effort of His stronger power. 
And justly set the gem above the flower." 



Brilliant objects have from time immemorial 
proved wonderfully fascinating to men. No won- 
der then that precious stones, those sparkling "blos- 
soms of the rock," to whose rare beauty nature has 
added the crowning gift of durability, should have 
kindled a passion for possession and inspired ardent 
search. 

In our own day the exceptional value of gems 
depends simply upon their use as ornaments, and 
their service in certain important optical and other 
instruments. With the ancients their importance 
rested on very different grounds. They attributed 
to these peerless little objects the most extraordi- 
nary gifts; they ascribed to them a spiritual as well 
as material potency — a power alike to cure diseases, 



32 



PRECIOUS STONES. 



to avert calamity, and to drive away the demons of 
the air. 

The belief indeed came to prevail, that the pre- 
siding genius of a man's fate might be carried about 
with him in the shape of a precious stone. This 
superstition, though to us it appears so absurd, was 




Fig. 19 — Egyptian Scarabseus cut in hard stone. 



quite in accordance with the general views which 
then prevailed regarding the moral and physical 
worlds. 

"A fact that governs all ancient history," says 
Hoefer, in his Histoire de la Chimie, "is the close 
alliance of religion with science. This alliance is 
one of the distinguishing characteristics of antiquity: 



HISTORICAL SURVEY. 33 

in it is found the solution of many of the problems 
that have disturbed the human mind." 

It is this dominating fact that offers a key to the 
special history of precious stones. 

Among the grand false or mistaken ideas held 
by the ancients, there are two that deserve all the 
attention of the historian and the philosopher. The 
first led them to consider man as a microcosm — a 
reduction in miniature of the entire universe, a 'little 
world' in exact counterpart of, the 'great world.' 
Accordingly every part of man's body was believed 
to have a corresponding part in the vast universe. 

The second was the conception of the soul of the 
world, according to which the souls of animated 
beings were but parts of the universal soul. At 
the moment of the dissolution of the body, said 
the philosophers of India, the soul, dtmd, very dif- 
ferent from the merely vital principle, will unite 
itself, if it is pure, with the great universal soul, 
paramdtmd, from which it emanated. If it is im- 
pure it will be condemned to submit to a certain 
number of transmigrations, that is to say, to ani- 
mate successively plants or animals, or even to be 
incarcerated in some mineral body until, purified of 
all imperfections, it is considered worthy of absorp- 
tion, miikti, into the Divinity. 

Thus minerals as well as animals and plants were 

to these philosophers living beings. 

3 



34 PRECIOUS STONES. 

They maintained also, that the world was an 
animal reuniting the two principles, active and 
passive; an idea that entered fundamentally into 
nearly all the systems of ancient philosophy. 

From India these theories passed into Egypt, 
whence they were transported to Greece by Plato, 
Pythagoras, and other philosophers. Confined for 
centuries to the European orient, they reappeared 




Figs. 20 dnd 21. — Egyptian Figures carved in hard stone. 

with some brilliancy at the commencement of the 
present era in the writings of philosophers of the 
school of Alexandria. In the mediaeval age, when 
the alchemists transported them into the mineral 
kingdom, they reigned supreme. 

If we examine, in connection with these ideas, 
the rank that was ascribed to precious stones, we 
shall find that they necessarily acquired a great im- 
portance. The beauty of their forms and the splen- 
dour of their colours could not fail to make them 



HISTORICAL SURVEY. 



35 



to be considered productions of an incomparable 
purity, and an epitome of all that nature held most 
perfect. To endow these mar- 
vellous products with properties 
in conformity with the prevailing 
idea»of their nature and origin 
was but a step farther, and accord- 
ingly we find attributed to them 
talismanic virtues and agencies 
of the utmost potency. 

"It would not be without in- 
terest," writes Babinet, "to follow 
the history of gems through that 
of humanity, from the ephod of 
Aaron to the pastoral cross of 
the Archbishop of Paris; from 
the offerings of rubies, sapphires, 
emeralds, diamonds, topazes, sar- 
donyx, amethysts, carbuncles, and loadstones in 




Fig. 22. — Cornelian en- 
graved: Egyptian. 




fig. 23. — Egyptian Ring of Cornelian. 



the temples of Jupiter and other pagan divinities, 
to the riches of the same nature which by the 



36 



PRECIOUS STONES. 



sixteenth century had accumulated in what was 
called the 'treasury' of Christian churches. There 
is still preserved at Rome an emerald of Peru, sent 
in homage to the pope after the conquest of that 
country. It should be remarked, however, that 
these precious stores, originating in the piety of the 





Figs. 24 and 25. — Egyptian Rings and Tablets engraved on both sides. 



faithful, have not always been faithfully respected. 
When the reformation of Luther and Calvin in 
German countries, and later, the French revolution 
in countries remaining Catholic, transferred these 
votive riches to the possession of the civil authorities, 
it is well known that many fraudulent substitutions 
had been made, and that paste had frequently 
replaced the primitive gem." 



HISTORICAL SURVEY. 37 

" Precious stones," continues Babinet, " have in 
all times been highly esteemed, and without doubt 
will continue to be so in all ages to come. Com- 
paring our modern luxury with the splendours of 
oriental courts and of Roman citizens enriched with 
the^poils of the world, we find ourselves inferior in 
many points, but not so far as diamonds are con- 
cerned. If in one of the brilliant reunions of the 
Tuileries, we calculate the value of the diamonds, 
even allowing deduction for false jewelry, we con- 
clude that our French riches, although more widely 
spread, do not fall a whit behind the much-vaunted 
riches of Rome." And this remark applies with 
equal justice to the brilliant assemblies of other 
modern capitals. 

The mythology of India refers to precious stones 
in terms that prove their general estimation in the 
most ancient ages: the songs and ballads of that 
country frequently mention these beautiful produc- 
tions. 

In Egypt a number of gems finely cut and en- 
graved with consummate skill have been found be- 
side mummies in tombs attributable to an extremely 
remote era. Their workmanship leads to the belief 
that the means employed by the ancient Egyptians 
in engraving hard stones did not dififer sensibly 
from those used at the present day. 

Types of these ancient jewels, copied from speci-- 



38 PRECIOUS STONES. ^ 

mens in the museum of the Louvre, are represented 
by Figs. 19 to 25. Fig. 22 is particularly interest- 
ing; it is a red cornelian bearing hieroglyphic char- 
acters, exquisitely engraved. 

The conquerors of Mexico found in the hands of 
the Incas a multitude of gems, cut and engraved 
with various images, which, according to Mexican 
traditions, had descended from a very remote 
period. 

In the Bible there are several passages that refer 
with technical distinctions to precious stones. The, 
most remarkable occurs in the description of the 
vesture of the high-priest, which was made, as the 
Scripture reads, "for glory and for beauty," and 
was adorned with symbolic gems. The ephod of 
Aaron was ornamented with two onyx stones, en- 
graved with the names of the twelve tribes of Israel. 
The breast-plate consisted of twelve precious stones, 
set in the form of a double square, and of a size 
that allowed each stone, with its setting, to occupy 
a space of 2^ ins. by 2 ins. 

Translators differ in their rendering of the Hebrew 
names applied to these sacred stones — a fact which 
need not surprise us when we consider how few 
particulars are given — but the following order, 
although differing somewhat from the arrangement 
of Calmet, is in accordance with the opinion of 
the most celebrated rabbis. 



HISTORICAL SURVEY. 

Order of the Stones in Aaron's Breast-plate. 



39 



Prim-US 
Ordo. 


I 

Oden. 

Cornelian. 

Reuben. 


Phideth. 
Topaz. 
Simeon. 


Barcketh. 

Emerald. 

Levi. 


Secmhdits 
Ordo. 


Nophecth. 
Ruby. 

JODAH. 


Saphir. 
Sapphire. 

IsSACHAR. 


6 
yaolam. 
Diamond. 
Zebulun. 


Tertius 
Ordo. 


Leschem. 

Hyacinth. 

Dan. 


8 

Schebo. 

Agate. 

Naphtali. 


9 

Achlamah. 

Amethyst. 

Gad. 


Qitartus 
Ordo. 


lO 

Tarschisch. 
Chrysolite. 

ASHER. 


II 

Schoham. 

Sardonyx. 

Joseph. 


12 

Jaspeh. 

Jasper. 

Benjamin. 



In the book of Job there are facts mentioned that 
have led some to attribute to the author a profound 
knowledge of metallurgy; and he mentions by name 
the precious stones, sapphire, onyx, ruby, and topaz; 
crystal also, and coral and pearls. Mention is also 
made of geological phenomena similar to those 
which have played a part in bringing these mineral 
treasures to light, and which c^re so familiar to the 
geologists of the present day. 

"He putteth forth his hand upon the rock; he 
overturneth the mountains by the roots ; he cutteth 
out rivers among the rocks, and his eye seeth every 
precious thing. He bindeth the floods from over- 
flowing, and the thing that is hid bringeth he forth 
to light." 



,40 PRECIOUS STONES. 

In the New Testament; the most remarkable 
passage in* which precious stones are mentioned is 
that in the Apocalypse describing the New Jeru- 
salem, "And the building of the wall of it was of 
jasper," we are told, "and the foundations of the 
wall of the city were garnished with all manner of 
precious stones." The precious stones were twelve 
in number, and they were arranged in order as 
below, where each has its colour placed opposite to 
it. 

Order of Precious Stones in the Wall of the New Jerusaletit 
( Vision of St. yohn). 

Jasper Dark opaque green. 

Sapphire [lafis laziili) . Opaque blue. 

Chalcedony Greenish blue. 

Emerald Bright transparent green. 

Sardonyx White and red. 

Sardius Bright red. 

Chrysolite Bright yellow. 

.-. — Beryl Bluish green. 

Topaz (or Peridot) . . . Yellowish green, 

■ Chrysoprasus Darker shade of same. 

Hyacinthus {Sapphire) . Dark shade of azure. 

Amethyst Violet. 

In the Iliad and Odyssey there are occasional 
metallurgic descriptions of much interest; and 
especially to be noted in regard to precious stones 
are the passages descriptive of the jewels of Juno. 

MEDICAL MINERALOGY. 

From the time of his first appearance upon the 
earth, man has been subject to malady and death. 
That is to say, medicine is as old as humanity. 



ASTROLOGICAL MINERALOGY. 4 1 

It is probable that the earliest medicines were 
derived from vegetables, and that certain animal 
substances were next made use of; but it was long 
before people thought of employing mineral sub- 
stances in medicine. This we first hear of in early- 
Greek history. 

Certain earths, generally aluminous, administered 
in various ways, were said to produce salutary 
effects. These earths were sold in little packages 
marked with different names, generally referring to 
the places of their origin. They were rendered still 
more efficacious by having a special seal affixed to 
them by the priests of various divinities, whence the 
term terra sigillata (sigillitmy a seal). Among the 
most celebrated of these "sealed earths" was the 
earth of Lemnos, sold by the priestesses of the 
temple of Ephesus, in packages stamped with a 
goat, the sacred seal of Diana. 

In the ancient pharmacopoeias, precious stones 
are counted among the most valuable remedies. 
Special virtues were attributed to the ruby, topaz, 
emerald, sapphire, and hyacinth, which were ren- 
dered famous in medicinal annals under the title of 
"The Five Precious Fragments." 

ASTROLOGICAL MINERALOGY. 

Astrological mineralogy had its origin in Chaldea. 
A work of Abolays, translated by Jehuda Mosca 



42 PRECIOUS STONES. 

about the middle of the thirteenth century, contains 
a catalogue of 325 stones, distributed by the Chal- 
dean astronomers among the twelve signs of the 
zodiac, according to the relationship supposed to 
exist between the different stones and the constel- 
lations. 

Later a single stone was specially consecrated to 
each sign of the zodiac, and consequently to each 
month of the year. 

An amulet was made of these twelve sacred 
stones ; so that as the constellations appeared suc- 
cessively above the horizon, the corresponding gems 
might always be on hand, to convey to the possessor 
the benign influences which they were then sup- 
posed to bestow. 

The following list comprises the twelve stones of 
the amulet, with their zodiacal signs and the months 
of the year to which they corresponded: — 

Garnet Aqttarius January. 

Amethyst Pisces February. 

Jasper Aries March. 

Sapphire ... . Taurus April. 

Agate Gemini May. 

Emerald Cancer June. 

Onyx Leo July- 
Cornelian Virgo August. 

Chrysolite .... Libra ....... September. 

Aquamarine .... Scorpio October. 

Topaz • . Sagittariiis November. 

Ruby Capricormis .... December. 

It is exceedingly probable that the origin of this 
superstition is to be traced to the twelve precious 



ASTROLOGICAL MINERALOGY. 43 

stones contained in the breast-plate of the Jewish 
high-priest. 

Traces of sacred, poetic, astrological, and medi- 
cal mineralogy frequently appear collectively, or in 
turn, in the treatises — even the most scientific — 
thatffrom the time of Homer until now, have been 
written upon precious stones. 

Herodotus, born 484 years before Christ, five 
centuries after Homer, has left us a great number 
of statements, and some of them very valuable, 
concerning mineral substances known in his time: 
but he does not make mention of any new substance 
appertaining to the class of precious stones. 

In the poems of Orpheus, attributed also to 
Onomacritus, and, in any case, as old as 450 B.C., 
there is evidence that the Greeks already attributed 
supernatural qualities to precious stones. 

In the following century Plato, whose vast intel- 
ligence embraced so many transcendental ideas, 
was led to examine the origin of precious stones. 
He believed that they were veritable living beings, 
produced by a sort of fermentation determined by 
the action of a vivifying spirit descending from the 
stars. He described the diamond, which he distin- 
guished from other precious stones as being a kind 
of kernel formed in gold; and supposed that it was 
the noblest and purest part of the metal that had 
condensed into a transparent mass. 



44 PRECIOUS STONES. 

Aristotle, born just a century after Herodotus, 
touches upon minerals only incidentally, at the 
end of his four books on Meteors, and sheds upon 
them no new light. 

Theophrastus, a pupil of Aristotle, wrote a trea- 
tise upon precious stones, only a part of which has 
reached us. Notwithstanding the defects of this 
work, in part attributable to the times and in part 
to the author, we are none the less indebted to 
Theophrastus for the description of a number of 
important mineral substances unknown before his 
time. 

We find also in this writer an idea which, taken by 
itself, is very singular: he divides the stones into two 
categories — male and female. When the reader 
remembers what has been said above, however, he 
will understand that there is nothing in this idea 
that is not in harmony with the general ideas of 
the ancients. 

Dioscorides, whose valuable writings appeared in 
the first century of our era, furnishes, in a minera- 
logic point of view, no information of importance. 
But in another aspect his works are exceedingly 
interesting, seeing that we find in them the full de- 
velopment of the idea that precious stones possess 
a multitude of secret virtues — an idea admitted 
without dispute by all his successors, to a time very 
closely approaching our own, and which we find 



ASTROLOGICAL MINERALOGY. 45 

still entertained by the inhabitants of the moun- 
tainous regions of Spain and Arabia. 

A few years after Dioscorides a work appeared, 
beyond all comparison in advance of its prede- 
cessors, the Natiwal History of Pliny. In this 
work, one of the most precious that we have in- 
herited from antiquity, we find a chapter exclu- 
sively devoted to precious stones: it is a chapter to 
which we shall find occasion to refer in the follow- 
ing pages. 

Leaving Pliny we must come down to the Arabs, 
ten centuries afterwards, before we find any new 
information upon minerals and precious stones. 
This we meet with first in the writings of Gerbert 
and Avicenna, 

Avicenna acquired in his lifetime a wide reputa- 
tion ; and although it was due as much to his tact 
as to his science, it remained unrivalled for many 
centuries. 

Among his writings there is a treatise upon 
stones, which comprehends results of great impor- 
tance. The chapter devoted to the origin of moun- 
tains deserves particular notice. It is in this chapter 
that the learned Arab, always maintaining the 
hypothetical method of argument, expounds with an 
extraordinary grandeur and clearness of insight the 
theory of upheavals, that of Neptunism and of 
Plutonism, and the mode of formation of alluvial 



46 PRECIOUS STONES. 

deposits: thus anticipating by eight centuries the 
results of modern science. 

Two hundred years after Avicenna there ap- 
peared one of the grandest figures of the middle 
ages — Albertus Magnus, or Albert the Great. 

Among the great works that we owe to this gifted 
man, or at least to his impulse and direction, is a 
treatise upon minerals, of which the illustrious 
chemist M. Dumas has said, " That which charac- 
terizes the treatise De Rebus Metallicis is the 
learned, precise, and often elegant exposition of 
the opinions of the ancients and of the Arabs; it 
is the methodical discussion of these which discloses 
at once the practised writer and the attentive 
observer." 

In this treatise Albertus Magnus discusses precious 
stones ; and while devoting a considerable space to 
the extraordinary properties of these beautiful pro- 
ductions, he carefully distinguishes a certain number 
of them, and indicates methods of obtaining several 
sorts of false gems. 

Another illustrious genius of the middle ages; — 
the friend and disciple of Albertus Magnus — St. 
Thomas Aquinas, whose voluminous works even 
surpass in extent those of his master, has written a 
treatise upon the Nature of Minerals, in which 
some very curious passages occur, especially on the 
fabrication of artificial stones. 



ASTROLOGICAL MINERALOGY. 47 

In glancing over the works of Arnault de 
Villeneuve, of Raymond Lully, of Paul of Cano- 
tanto, of Isaac the Hollander, &c., we find a certain 
amount of space devoted to precious stones ; but no 
new idea worthy of note. Thus the end of the 
fifteenth century is reached, and we emerge from 
the medieval age. 

Upon the threshold of the Renaissance a sin- 
gular character appears, Jerome Cardan (born in 
1 501), who furnishes us with some valuable sugges- 
tions. Several works of Cardan, published after his 
death, contain some rather absurd passages; but 
in his treatise De Subtilitate, the careful student 
finds many ideas which prove that the author pos- 
sessed great intelligence, and beneath an air of 
bonhommie a veritable sagacity. 

Cardan designates under the generic name of 
gems all the brilliant stones, and reserves the name 
of precious stones for those which are not only 
brilliant, but rare, and of small dimensions. These 
precious stones he divides into three classes: 1st, 
those which are brilliant and transparent, as the 
diamond ; 2d, those which are opaque, like the 
onyx; 3d, those which are formed by the con- 
junction of the two other kinds, as the jasper. 

This is very nearly the same classification as 
that employed by Caire, three centuries after 
Cardan. 



48 PRECIOUS STONES. 

According to Cardan, precious stones are engen- 
dered ("in the same manner as the infant from the 
maternal blood") by juices that distil from precious 
minerals in the cavities of the rocks: the diamond, 
the emerald, and the opal from gold ; the sapphire 
from silver; and the carbuncle, the amethyst, and 
the garnet from iron. 

In enumerating the flaws or imperfections which 
may be presented by precious stones, he makes a 
remarkable reflection, and one which has been con- 
sidered an ingenious plea for excusing certain well- 
known imperfections of his own. 

"In precious stones," he says, "imperfections are 
in reality less common than in animals and vege- 
tables; but they are more conspicuous in jewels, 
simply because their nature is more brilliant and 
more rare. For the same reason, great men appear 
to have more vices than common mortals; but this 
is a delusion and an error. The lustre of their 
fame and the splendour of their names render their 
faults only the more apparent; while the ignorant 
vulgar, under favour of their obscurity, escape 
having their vices noticed." 

It was admitted without question, in the time of 
Cardan, that precious stones were living beings. 

" And not only do precious stones live, but they 
suffer illness, old age, and death." 

He then speaks of the different virtues possessed 



ASTROLOGICAL MINERALOGY. 49 

by precious stones. The hyacinth preserves from 
thunder-storms and from pestilence, and induces 
sleep. This last quality was attributed to it by 
Albertus Magnus, Without precisely rejecting this 
notion, Cardan confesses that he carries ordinarily a 
vsfy large hyacinth, and that it has never appeared 
to contribute anything towards making him sleep; 
but he adds immediately, and with perfect naivete, 
that his hyacinth has not the true colour, and may 
possibly be far from good. It was also believed 
that the hyacinth increased riches, augmented 
power, fortified the heart, brought joy to the soul, 
&c. 

He describes the turquoise, which, mounted in a 
ring, secures the horseman from all injury if he falls 
from his horse ; and adds, " I have a beautiful tur- 
quoise which was given me for a keepsake, but it 
has never occurred to me to test its virtues, as I do 
not care, for sake of the experiment, to fall from 
my horse," 

It is not necessary to multiply examples to give 
an idea of the remarkable properties ascribed to 
gems in antiquity, and in the middle ages. In 
discussing this subject M. Babinet makes the fol- 
lowing striking remarks: — 

** For all maladies of a nervous or moral nature, 

where imagination might exert a great influence, 

precious stones were certainly a sovereign remedy. 
4 



50 PRECIOUS STONES. 

In saying to such an invalid that an emerald placed 
under his pillow would drive away melancholy, dis- 
pel nightmare, calm the palpitations of the heart, 
induce agreeable thoughts, bring success to enter- 
prises, and dissipate the anxieties of the soul, a cure 
was certain to be effected simply by the faith which 
the invalid had in the efficacy of the remedy. The 
hope of cure in such affections is the cure itself; and 
in all the numerous cases where the mind has had 
an influence upon the bodily system, the imaginary 
cause must produce a very real effect. Finally, 
that eternal deception of the human spirit, which 
registers all the cures, but does not take into ac- 
count the cases where the curative means have failed 
of their end, contributed to maintain the belief in 
the occult virtues of precious stones. It is not half a 
century ago since sufferers would borrow from rich 
families gems mounted in rings, to apply to afflicted 
parts. When the trinket was introduced into the 
mouth as a cure for toothache, sore throat, or ear-ache, 
the precaution was taken to secure it with a strong 
thread, lest it should be swallowed by the patient. 

" It is unnecessary to say that if we are asked to- 
day, whither are gone all these beliefs "which to our 
fathers were incontestable, we answer that they are 
gone with the 'lunar influences* so powerful in the 
time of Louis XIV., to take their place in the 
vast limbo of human errors." 



CLASSIFICATION. 51 

It remains to us now to say a few words concern- 
ing the order that we shall follow in the particular 
description of precious stones. 

In spite of all the discussions that have arisen on 
this subject, and the great number of classifications 
presented by different authors who have occupied 
themselves with the question, there does not exist, 
and there cannot exist, any general and natural 
classification of precious stones. The reason is very 
simple: these substances being what we may call 
particular cases in nature, it is not possible to arrange 
them itt series. By choosing any one of their 
general characteristics, crystalline form, refraction 
single or double, composition, or commercial value, 
&c., the geometrician, the physicist, the chemist, 
and the merchant can easily establish a classification 
answering more or less completely to their special 
end ; but this is not a natural classification. 

Without discussing or criticizing the different 
methods proposed, we shall adopt in this book a 
classification based upon chemical composition. 

If there should be placed upon a table a specimen 
of every kind of precious stone known at the present 
day, it would be possible to separate them imme- 
diately, according to their chemical composition, 
into three perfectly defined groups. 

The first comprises a single precious stone, the 
diamond. Its constituent principle is carbon. 



52 PRECIOUS STONES. 

The second includes the sapphire, the ruby, the 
topaz, the amethyst, the emerald, &c. — stones of 
which alumina is the base. 

The third comprises stones whose base is silica — 
the opals, the agates, &c.. 

Carbon, alumina, silica: this is the order of im- 
portance of the three substances which enter essen- 
tially into the composition of precious stones; and 
in this order we shall arrange the chapters devoted 
to the history of all the gems which each division 
includes. 

But before studying these groups, two descriptive 
terms applied to precious stones should be explained, 
the terms Oriental and Occidental. 

Originally these words were applied in their 
literal sense; but at the present time they are re- 
tained in commercial parlance, not to indicate the 
regions from which the precious stones are .brought, 
but simply to establish between stones of the same 
name a comparative value. The most precious 
variety of any precious stone is called Oriental, and 
the inferior variety Occidental, whatever may be the 
countries in which they are found. 



PART III. 



' Le Diamant 1 c est I'art de choses ideales, 
Et ces rayons d'argent. d'or, de pourpre et d'azur 
Ne cessent de lancer les deux lueurs egales 
De pensers les plus beaux, de I'amour le plus dure." 



The diamond, which for a long time has been 
considered the most precious of gems, has been 
known from early antiquity. 

Its name adamant, a name that can be recog- 
nized in nearly all its modern appellations, was given 
by the Greeks, and signifies "the indomitable." 

The excessive hardness of the diamond quite 
justifies this designation; but we find from the 
authors of antiquity that the ancients attributed to 
this stone certain other properties that it can by no 
means lay claim to, such as that of not becoming 
warm when heat was applied to it, and above all, 
that of resisting, without breaking, the blow of a 
hammer. The latter property is mentioned both 
by Lucretius and Pliny, not to go farther back. 

" Adamantina saxa 

Prima acie constant, ictus contemnere sueta." 

"The test of all these diamonds," says Pliny, "is 
made upon an anvil by blows of the hammer, and 
their repulsion for iron is such that they make the 



54 PRECIOUS STONES. 

hammer fly in pieces, and sometimes the anvil 
itself is broken." This error maintained its ground 
down to a very late period. Thus in the year 1476, 
when, after the battle of Morat, the Swiss soldiers 
seized upon the tent of Charles the Bold, they 
found in it, among other treasures, a certain num- 
ber of diamonds, and in order to test whether they 
were genuine struck them with hammers and 
hatchets, and of course broke them in pieces. 

The diamonds earliest known to the Romans 
were furnished by Ethiopia ; but when Pliny wrote, 
during the first half century of our era, they had 
already been brought from India; and thencefor- 
ward, until the eighteenth century, no diamond mines 
were known but those of the East Indies — in the 
empire of the Mogul, and in the island of Borneo. 

Then the discovery of the Brazilian diamond dis- 
tricts created an excitement throughout the world ; 
and, considerably more than a century afterwards, 
the opening of the diamond-fields of South Africa, 
has once more "revolutionized the trade." 

In 1829, in accordance with a judgment ex- 
pressed by Humboldt, diamonds were found in the 
Ural Mountains; they have also been obtained from 
Sumatra, Java, South Carolina, Georgia, Alaska, 
Arizona, Mexico, and Australia; but the production 
has been of too isolated occurrence to indicate any 
new centres of commerce. 



DIAMOND MINES OF INDIA. 55 

The accepted diamond countries of history and 
commerce are India, Brazil, and South Africa. 



DIAMOND MINES OF INDIA. 

•First of all, for size and beauty, the Indian dia- 
monds are famed: "diamonds of Golconda" have 
become a synonym for preciousness and brilliancy. 
These gems were brought, not from the immediate 
vicinity of the fortress of Golconda, but from the 
mines of Raolconda and other localities situated 
in the territory of the Golconda kings. The mines 
were many years ago ceded to the English, but 
they have long since been abandoned; and it is 
believed that they are exhausted. Their treasures, 
however, shine in the coronets of every nation of the 
globe. 

Diamond localities are numerous in Hindostan, 
and in Borneo, whose "Landak" diamonds have 
been especially prized ; but many of these localities 
have ceased to be productive, and their names are 
becoming obsolete. In Tavernier's time the Gol- 
conda mines employed 60,000 people, and had 
already proved so rich that, as Ferishta records, 
the Sultan Mahmoud (A.D. 1177-1206) left in his 
treasury more than four hundred pounds weight of 
these precious gems. 

It is from the descriptions of Tavernier, a 



56 PRECIOUS STONES. 

French jeweller who travelled through Turkey, 
Persia, and the Indies in the latter part of the seven- 
teenth century, that we derive the most vivid accounts 
of the Indian mines. 

"I visited first," he writes, "a mine in the terri- 
tory of the kings of Visapoor, in a place called 
Raolconda^ five days from Golconda, and eight or 
nine frbm Visapoor. 

"All around the place where the diamonds are 
found the ground is sandy and full of rocks, and 
covered with coppice, somewhat like the environs of 
Fontainebleau. In these rocks are numerous veins, 
sometimes half a finger, sometimes a whole finger 
wide; and the miners have little iron rods, crooked 
at the end, which they thrust into the veins to dis- 
lodge the sand or earth in which the diamonds are 
found. . . . After this part of the work is done, 
the earth and sand is passed through two or three 
washings, and is carefully searched to see if it have 
any diamonds. It is from this source that the 
clearest stones and those of finest water are taken. 
The only evil is, that to render more easy the ex- 
traction of the sand from the rocks, such strong 
blows are given with a great lever of iron, that they 
shock {etonne) the diamond and produce flaws." 

Tavernier visited also the mine of Garree, seven 
days east from Golconda, and the diamond-yielding 
bed of the river Gooel, in the kingdom of Bengal. 



DIAMOND MINES OF INDIA. 57 

He relates, with very picturesque and lifelike de- 
tails, his various affairs with the diamond mer- 
chants; and announces the somewhat remarkable 
fact, that the chief negotiators in the sale of dia- 
monds in India were boys not over sixteen years 
of Rge. 

" It is pleasant," says Tavernier, " to see the chil- 
dren of these merchants, and of other people of the 
country, from the age of ten to that of fifteen or six- 
teen, coming every morning and seating themselves 
under a large tree in the market-place of the town. 
Each has his diamond weights in a little pouch hang- 
ing at one side, and at the other side a purse attached 
to his girdle, and containing, in some cases, as many 
as six hundred gold pagodas. There they sit and 
wait until some one comes to sell them diamonds, it 
may be from the vicinity, or from some other mine. 
When anyone comes with something for them he 
places it in the hands of the eldest of the boys, who 
is, as it were, the chief of the band. H e looks at it, and 
hands it to the one next him, and so it passes from 
hand to hand till it return to the first, not a word 
being spoken by any of them ; the eldest boy then 
asks the price, in order to make a bargain, if pos- 
sible, and if he happen to buy it too dear he has to 
take it on his own account." 

When evening comes the boys bring together all 
the stones they have bought, examine them, and 



58 PRECIOUS STONES. 

arrange them according to their water, their weight, 
and their clearness. Then they put upon each its 
price, as near as possible that at which they would 
sell to the merchants, and by the latter price they 
see how much profit they will have. They now 
carry them to the large merchants, who have al- 
ways great numbers of stones to assort, and all the 
profit is divided among the boys, the one who acts 
as their chief receiving one-fourth per cent, more 
than the others. Young as they are, adds Taver- 
nier, they know the price of every stone so well 
that if any of them have made a purchase, and is 
willing to lose a half per cent, another will give 
him his money. 

He describes the devices resorted to by jewel- 
dealers to conceal any defects there might be in 
their merchandise ; and the skilful manner of plan- 
ning the cutting so as to dispose of flaws. 

From the very moment of its recognition, it 
would seem that the diamond quickened the wits of 
its possessor, and aroused an ambition of brilliant 
gain. Even the poor slave in the mines managed 
occasionally to elude the sleepless vigilance of the 
overseers, and conceal a valuable gem. Tavernier 
saw in one of the Indian mines a poor wretch who, to 
appropriate to himself a fine diamond of the dimen- 
sions shown in Fig. 27, had forced it into the corner 
of his eye in such a way as to conceal it completely. 




Fig. 26. — View in a Diamond District of Brazil. 



DIAMOND MINES OF BRAZIL. 6l 

According to Heynes' account of the mines of 
Hindostan, the diamond is found in alluvial soil, or 
the most recent rocks. "Shallow pits are exca- 
vated to the diamond beds, which lie about eight 



Fig. 27. — Size of a Diamond hidden by a slave in the corner of his eye. 

feet below the surface of the soil, in a conglo- 
merate of rounded stones under two distinct layers; 
the uppermost, a mixture of sand, gravel, and loam; 
and the other, thick black clay or mud." 

DIAMOND MINES OF BRAZIL. 

Brazilian diamonds are found in the district of 
Minas Geraes, at San Paulo, in the beds of various 
rivers, and at Serro Frio, or Cold Mountain, a 
lofty plateau measuring eight leagues by sixteen. 
The most productive districts of late are Matto 
Grosso and Bahia. 

The diamonds occur usually in alluvial soil, en- 
veloped in a conglomerate formed of rounded white 
quartz pebbles and light-coloured sand. The miners 
have names for each variety of soil ; as — 

Grupiaray the unused bed of a river. 



62 PRECIOUS STONES. 

Biirgalhoa, angular fragments of rocks that strew 
the ground; and 

Cascalho, the generic name of all. 

When diamonds were first found by the gold 
hunters of Brazil, no notion was formed of their 
value. They were used for counters in card-play- 
ing. But at last a native named Bernardo Lobo, 
who had journeyed to the East Indies, and had 
seen uncut diamonds there, recognized the nature 
of these disregarded pebbles. 

The news of the discovery spread across the 
world, and its first effect was a panic in the dia- 
mond trade. Some time had to elapse before the 
dealers in Indian gems could reconcile themselves 
to any rival that might depreciate the treasures of 
the Orient. 

Meanwhile upon the inhabitants of the diamond 
districts the discovery acted like a curse; and to 
the bitter sorrows of persecution were added the 
horrors of earthquake and drought. "It seemed as 
if the genii," says Emmanuel, "guardians of the 
treasure, were indignant at the presumption of 
man, and tried by every means to prevent the dis- 
persion of the buried treasure." 

But the riches of the province were incalculable. 
The search for gold no longer offered any attrac- 
tion ; the children gathered the precious dust after 
the rains. The energies of the gold-hunters, were 



DIAMOND MINES OF BRAZIL. 65 

diverted to diamond finding; care was taken even 
to examine the crops of all kinds of killed fowls, 
for diamonds had been found in this way; a negro 
found a gem of five carats adhering to a cabbage 
which he had plucked for his dinner. 

As the search became organized, the waters of 
the rivers were diverted at the dry season into canals. 
The soil was dug to the depth of about ten feet, and 
deposited in heaps near the washing huts. These 
huts were furnished with elevated seats for the over- 
seers, who watched incessantly the long troughs, 
called canoes, in which the cascalho was washed. 

When a slave found a diamond of 18 carats he 
received his freedom, and was crowned with floAvers, 
and led in a triumphal procession, amid the rejoicings 
of his friends. 

Modern appliances and innovations have altered 
somewhat the primitive modes of diamond washing, 
but the leading features remain the same, the object 
being to wash away the finer particles of soil, and 
obtain the gems from the residue. 

In 1754, a slave, transported from MinasiiGeraes 
to Bahia, discovered, from analogies of soil that led 
to immediate diamond-seeking, the wonderfully rich 
district of Bahia. It is now estimated that the 
Brazils export annually from Rio Janeiro an amount 
of rough diamonds averaging in value from four to 
five millions of dollars. 



66 PRECIOUS STONES. 



DIAMOND MINES OF SOUTH AFRICA. 

In the autumn of 1868 news reached England 
from Capetown that diamonds had been found in 
the gold districts on Orange River, midway between 
the eastern and western coasts of South Africa. 
And in the spring of the following year all doubts 
that had been either genuine, or instigated by 
jealous fear of disturbance in the diamond trade, 
were silenced by the discovery of the "African 
Koh-i-noor," valued at about $150,000. 

This splendid stone, destined to create a stir that 
should widen into the most distant circles, was 
found by a poor herdsman, who had the supreme 
happiness to dispose of it for five hundred sheep, 
ten head of cattle, and a horse. It was taken to 
Capetown, where an injunction was placed upon it 
by emissaries of Waterboer, chief of the Griquas, 
who claimed it as the possession of his own terri- 
tory; but, for lack of proof, the injunction was re- 
moved, and the diamond finally reached England. 
From that time tidings of new discoveries became 
more and more frequent; and the Griquas began 
successfully to search the beds of their streams. 

By 1870 public attention had become thoroughly 
aroused. Already enterprising men and capitalists, 
among them Coster of Amsterdam, were on the 



DIAMOND MINES OF SOUTH AFRICA. 6"] 

field. The diamond districts of the Vaal had 
proved an entire success. Seventy-two large dia- 
monds were found at Pniel in one week; ninety-one 
were unearthed by a single digger within a fortnight; 
diamonds to the amount of $500>000 had been 
picked up by Europeans. 

A regular organization of diggers was formed 
near the mission station of Pniel, — itself, as after- 
wards proved, one of the richest localities. A 
" digging committee " apportioned to each man so 
many square feet, to be worked at once or aban- 
doned. The diamond claims of these " dry dig- 
gings " came eventually to be sunk sixty feet below 
the surface; sometimes seventeen feet of red sand 
was removed before diamondiferous soil could be 
reached. The best yield occurred generally at the 
depth of twenty or twenty-five feet. The natives 
worked in these pits with pick and shovel; above 
them were the sorting-tables, some under cover, 
some not; and between the crowded pits carts 
crawled along, bringing burdens of gravel to the 
tables, to be sorted by the Europeans. 

The excitement had now reached its height. 
Not only did every town of South Africa empty it- 
self of men for "the diggings," but diamond-hunters 
made their appearance from every quarter of the 
globe. There were forty thousand people within a 
line of seventy miles upon the banks of the Vaal 



68 PRECIOUS STONES. 

River. Hotels, shops, music-halls flourished; two 
newspapers were started. One after another new 
diamond-fields were brought to light. Du Toit's Pan, 
De Beers, Pniel, New Rush, and Colesberg Kopje 
opened their dazzling mines. 

The rival claims of different routes from the 
coast were contested with the utmost zeal. Rail- 
ways and telegraphs were projected, and modern 
machines were hastened to the scene. The mines 
were pronounced the richest in the world. Dia- 
monds weighing from 20 to 30 carats were not 
unusual ; and among the exceptional treasures 
found were diamonds weighing considerably more 
than 100 carats; including the beautiful "Star of 
Beaufort," and the " Star of Diamonds," weighing 
I02j4 carats; and a lovely stone, which attracted 
especial attention by exhibiting, under the micro- 
scope, an aspect of pointed mountain summits, 
lighted by vivid sunlight with all the colours of the 
rainbow. Rubies and turquoises were also found. 

But all these successes were not unalloyed. There 
were droughts, and fevers, and mournful death-lists. 
There were threatened invasions of the Caffres that 
kept all the white men armed; and frauds that 
occasioned lynch-law mobs; and annoyances on the 
frontiers. And there were endless disputes of 
boundaries and territorial rights, not altogether 
quelled when, to the joy of the miners, the British 



DIAMOND MINES OF SOUTH AFRICA. 69 

flag was hoisted on the diamond-fields, Nov. 1871 ; 
and the district south and west of the Vaal, known 
as West Griqualand, was proclaimed under the 
protection of the crown. 

The South African diamonds arc found over 
m«ny hundred square miles of territory. The prin- 
cipal diggings are situated in the extensive valley 
of the Vaal river, to the north-east of the Orange 
River Free State, and within the boundary of the 
Cape Colony as now defined. The country here 
rises into long stony ridges, called kopjes, consisting 
of irregular fragments of hard rock imbedded in 
ferruginous gravel, which varies in character and 
compactness, being sometimes quite loose and 
sometimes forming a compact lime-cemented mass. 
It is in this gravel that the diamonds are found. 
They occur at various depths down to twenty feet 
or more, but the usual depth is from two to six feet 
below the surface. " The manner of working is 
simple enough. A claim, or piece of ground thirty 
feet square, is occupied by two diggers in partner- 
ship, assisted by their black servants. They re- 
move the loose blocks of stone, which are cast aside ; 
they take up the gravel and sift it thoroughly, 
cither in a dry state, or with abundance of water in 
a sieve rocked by a cradle. When the pebbles 
have been thus separated from the sand, they are 
cleansed, and placed upon the sorting-table to be 



70 PRECIOUS STONES. 

carefully examined for any diamonds that may lie 
among them." 

Some fears were entertained as 1872 opened with 
still brightening prospects, that the large numbers of 
stones found might produce a depreciation in value; 
but such is the unprecedented demand for diamonds, 
these fears have not yet been realized. The "off 
colour" of South African diamonds only enhances 
the value of the translucent and colourless stones of 
Brazil and India ; and their large size and extreme 
brilliancy finds for them an ample appreciation. It 
is estimated that the diamonds exported from 
Capetown during the year 1871 amounted in value 
to S;, 5 00, 000. 

WEIGHT AND VALUE OF DIAMONDS. 

The diamond is known in three different mole- 
cular states, forming a graduated series that is very 
remarkable. It is crystallized, crystalline, and 
amorphous. 

The crystallized diamond is the diamond "par 
excellence ;" it is that which, when cut, is used in 
jewelry. 

The crystalline diamond cannot be cut. It bears 
in commerce the name of "boart," and is reduced 
to powder for cutting crystallized gems. 

The amorphous diamond is of a steel-gray colour 



WEIGHT AND VALUE. 7 1 

and quite opaque. It occurs in sandstone of very- 
old formation, and is found in Bahia, and of late in 
Mexico. It has no utility when cut, but reduced to 
powder it is used for polishing diamonds and other 
gems, and is especially prized by the watchmakers 
of ^Switzerland. Its hardness is identical with that 
of the crystallized diamond ; its specific gravity is 
3*oi2 to 3"Oi6. It is not used to so good advantage 
in proportion to its weight as "boart." It is known 
in commerce under the name of carbonate, or car- 
bonic diamond. 

Crystallized diamonds in their natural state are 
called "rough diamonds." 

The diamond is always sold by weight. The 
standard of weight for all precious stones is the 
carat; a name derived, it is said, from the seeds of 
a pod-bearing plant used in the East to measure 
gold dust. The carat is 4 grains ; that is, diamond 
grains, which differ slightly from troy grains, as it 
takes five of the former to weigh four of the latter; 
or more exactly, one carat = 3' 174 gr. troy. 

The carat is universally employed in the com- 
merce of jewelry, but it is not rigorously the same 
in all countries. The following are the weights of 
the different carats in milligrammes: — 

Brazil, 205750 

France, 205 '500 

England, 205 '409 

Holland, 205 '044 

Spain, 205*393 



^2 PRECIOUS STONES. 

The carat is divided into i \, \, j\, ^V- tt of 
the carat. The table of weights of a jeweller's 
balance should contain from the weight of a thou- 
sand carats to these fractions. 

The balance employed by dealers in pre- 
cious stones is a simple little balance which is 
held in the hand: and yet "such is the experienced 
quickness of the lapidary," says M. Helphen, "that 
the balance of the assayer will never find him wrong 
by even the 64th part of a carat." 

Rough crystallized diamonds are valued at from 
162 to 19 dollars thecarat, for assorted lots containing 
no diamonds of more than one carat. Above this 
weight prices are a different affair. 

The rule made known two hundred years ago by 
Tavernier, that "the prices of two diamonds are 
proportioned to the squares of their weights," is en- 
dorsed by some modern lapidaries. According to this 
rule, since a one-carat stone of the first water, well cut 
and without flaws, is valued at about $93, a stone of 
two carats should be worth four times that, or $372; 
and one of three carats, nine times as much, or $837. 

But statistics show that this rule, which was quite 
true in the time of Jeffries and Tavernier, is no 
longer applicable; it assigns to diamonds a higher 
price than in commerce they really bring. 

A table is given here, which not only establishes 
this fact, but which also furnishes other interesting 



WEIGHT AND VALUE. 



73 



conclusions. It is a table showing the prices of 
diamonds in the years 1606, 1750, 1865, and 1867. 

Comparative Values of Diamonds in 1606, 1750, 1865, and 1867. 



Brilliants. 


1606. 


1750. 


1865. 


1867. 




Dols. cts. 


Dols. cts. 


Dols. cts. 


Dols. cts. 


^ carat 


— 


— 


25 48 


28 08 


% „ 










— 


— 


44 26 


51 52 


I )> 










loi 37 


37 57 


84 25 


98 39 


ij< ,. 










172 42 


58 59 


131 31 


164 05 


1V2 „ 










273 97 


84 44 


178 18 


210 92 


iK „ 










354 88 


"4 57 


225 06 


257 79 


2 J. 










405 85 


150 10 


304 8s 


375 16 


2^ „ 










456 81 


189 S3 


328 29 


422 03 


2K ,. 










558 55 


234 36 


453 46 


516 15 


2% ,. 










761 48 


283 27 


468 90 


562 65 


3 










914 37 


337 59 


586 08 


656 39 


sK „ 










— 


— 


632 95 


703 26 


3% .. 










1015 56 


395 80 


703 26 


821 19 


3% „ 










— 


— 


821 19 


890 94 


4 










1219 04 


459 42 


— 


— 


4}i ,. 










— 


— 


1078 42 


1125 30 


4% „ 










1421 97 


677 04 


1172 17 


1406 71 


i% ,. 










— 


— 


1312 97 


1547 33 


5 










1624 71 


937 81 


1500 46 


1641 07 



VALUES OF DIAMONDS IN 1872 
[A Table prepared by Mr. Hermann, Preside7it of the New York 

Diamond Company). 
Melee, per carat, from $60 to 



Melange, 

Brilliants of 
Yi carat, 



^% 
^% 
2 

2K 
^% 
2K 



Value of Brilliants in Currency. 
Brilliants of 



$100 to $110 



^35 




3 carats, 


60 




3% „ 


100 to 


$I2S 


3% „ 


150 to 


175 


3% „ 


200 to 


225 


4 


250 to 


27s 


4% „ 


300 to 


325 


4V2 „ 


350 to 


375 


4% ,. 


400 to 


425 


5 


450 to 


500 





$500 to §550 

600 to 650 

700 to 750 

800 to 850 

900 to 950 

1000 to 1050 

HOC to 1150 

1200 to 1250 

1300 to 1400 



74 PRECIOUS STONES. 

The prices of the preceding table refer only to 
diamonds of the first quality, and without a flaw. 

One sees immediately that the rule of Tavernier 
is completely at fault. For by his rule the value of 
the one carat, being estimated in 1867 at $98, 39c., 
a diamond of two carats should have been worth 
$393, 56c., while in reality it brought $375, i6c.; and 
a diamond of five carats should have been worth 
twenty-five times as much, $2459, 75c,, when it 
brought actually only 111641, 7c. 

Another point that strikes the attention in in- 
specting this table, is the extraordinary depression 
in the price of diamonds in the middle of the 
eighteenth century. It was about that time that 
the discovery of the diamond districts of Bahia 
occasioned a panic in the diamond market. 

Lastly, the table shows that, absolutely, the price 

of diamonds was nearly the same in 1606 as in 

1867; but when we take into account the difference in 

the value of money at these two epochs, we see that 

diamonds were really much dearer 

at the beginning of the seventeenth 

century than they are now. 

Large diamonds are exceedingly 
rare. It is estimated that among ten 

Fig. 29. — Dimensions of 

a Brilliant of 10 carats, thousand diamonds hardly one will 
be found often carats weight; that is to say, of the 
size represented by Fig. 29. 




COMPOSITION OF DIAMOND. 75 



COMPOSITION OF THE DIAMOND. 

The ancients had no suspicion of the true 
natwre of the diamond. To have any idea of this 
subject, it was necessary that the bases of modern 
chemistry should be established, or at least that 
the complex phenomenon of combustion should 
have received its true explanation. Newton sus- 
pected from its wonderful refractive power that the 
diamond was combustible, but even as late as the 
middle of the eighteenth century, the definition of 
its composition, given in a standard work on physics, 
was — "the purest and finest earth, the most ethereal 
fire, and the most limpid watery 

The first important fact relative to the nature of 
the diamond was established by Boyle about the 
middle of the seventeenth century. He showed 
that under the influence of a great heat the dia- 
mond disappeared. A little later, in 1694, Cosmo 
III., Grand-duke of Tuscany, had a diamond sub- 
jected at Florence to the intense heat of the sun's 
rays, by aid of a concave mirror. The experiment 
was conducted by Averini, preceptor of the Prince 
John Gaston, son of Cosmo, and Targioni, member 
of the Academy del Cimento. The diamond first 
split, then emitted sparks, and finally disappeared. 



•J^ PRECIOUS STONES. 

This experiment was repeated at Vienna by 
Francis Stephen of Lorraine, afterwards Francis I. 
of Austria. The sun's rays were replaced by the 
fire of a furnace, with the same result. Nearly a 
hundred years after the experiment at Florence it 
was renewed in Paris by D'Arcet, Rouelle, and 
Macquer. On the 26th of July, 1771, these savants 
burned in the laboratory of Macquer a beautiful 
diamond furnished by an amateur, Godfrey de 
Villetaneuse. That the diamond had disappeared 
was certain, but the question arose whether it had 
actually burned or was merely volatilized. 

In the midst of the discussion, Le Blanc, a cele- 
brated jeweller of the day, ignoring the experiments 
carried out at Florence, Vienna, and Paris, affirmed 
that fire had no effect upon the diamond. He had 
frequently, he said, submitted diamonds to a high 
temperature to remove certain defects, and the heat 
had never in the least degree deteriorated the 
stone. 

To prove his assertion he tried an experiment 
before a great number of spectators in the labora- 
tory of Rouelle. He enveloped a diamond in a 
mixture of lime and charcoal dust, introduced it 
into a crucible, and exposed it to a violent heat. 
After about three hours the interior of the crucible 
was examined, and nothing was found there but the 
little box that the diamond had occupied. The 



COMPOSITION OF DIAMOND. 7/ 

experiment had resulted like the others, and Le 
Blanc retired amid the acclamations of his op- 
ponents, "without his diamond, but still uncon- 
vinced." 

Light had now begun to dawn upon the question, 
but it was still far from being settled. Accordingly 
Cadet, Macquer, and the illustrious Lavoisier made 
preparations for new experiments on the subject, 
when a skilful lapidary named Maillard presented 
himself before them, and maintained, as Le Blanc 
had done, that fire had no effect on the diamond. 
He offered to submit three diamonds to the most 
prolonged and intense heat, but he stipulated that 
he should be allowed to carry out the experiment 
in his own way. 

This being granted, Maillard took the bowl of a 
tobacco-pipe, placed the three diamonds in it in 
the midst of charcoal powder closely packed, closed 
the mouth of the pipe with a cover of iron, and then 
shut up the whole in a crucible filled with chalk 
and covered with a siliceous coating. (See Fig. 30.) 
The crucible was now subjected to a temperature 
such that at the end of four hours it was com- 
pletely soft and on the point of melting, when the 
fire was slackened. After the crucible had been 
allowed to cool it was carefully broken open, the 
pipe-bowl was found to be entire, with the char- 
coal in it as black as at first; and in the midst of 



78 PRECIOUS STONES. 

this the three diamonds, in every respect unaltered 
and uninjured. 

Some diamonds prepared by Maillard, and sub- 
mitted for twenty-four hours to the enormous tern- 




Fig. 30. — Maillard's Experiment. 

perature of a porcelain furnace, resisted the heat 
like the preceding. 

Analogous experiments were made in different 
parts of Europe, sometimes with the one, sometimes 
with the other of the preceding results. The facts 
remained inexplicable till — on the principal pheno- 



COMPOSITION OF DIAMOND. 79 

mena of combustion being established — it was 
noticed that the diamond had always disappeared 
when it had been heated in the presence of air, 
while it had undergone no modification when re- 
moved from the action of the air by means of sub- 
stances such as powdered charcoal, lime, &c. 

Arrived at this stage, the question could not long 
remain unsolved; and the solution was soon fur- 
nished by two of the creators of the science of 
chemistry — Humphry Davy in England, and La- 
voisier in France, 

"And what is the diamond?" asks Babinet, who 
has such a quick eye to the poetry of science. "The 
most precious thing in the whole world. And what 
is carbon.'' The most common material that is 
known ; one that not only exists in vast quantities 
in the bowels of the earth, but that plants and trees 
of every kind contain, in an inconceivable quantity. 
Silver can hardly pay for the diamond; for if we 
imagine a diamond of the weight of a twenty-five 
franc piece, it would weigh about 125 carats, and 
cost at least four millions of francs ; while an equal 
weight of carbon, even having recourse to the 
smallest copper pieces, would have no appreciable 
value. And yet the diamond and carbon are iden- 
tical. Diamond is crystallized carbon." 

Everyone knows the pungent gas that escapes 
from fermented liquors — cider, beer, wine, &c. — and 



So PRECIOUS STONES. 

is introduced artificially into aerated waters. It is 
formed by the combination of carbon with one of 
the elements of the air (oxygen), and is called by 
chemists carbonic acid. This substance is produced 
whenever carbon, or substances which contain car- 
bon, are burned in contact with the air; and not the 
slightest trace of it is ever found, if the substance 
burned does not contain carbon. 

After this grand fact had been established, it 
was very easy to find out if the diamond contained 
carbon, and also whether this was its sole constituent. 
To settle the first question, the celebrated Lavoisier 
had recourse to the experiment represented by 

Fig. 31- 

A bell-glass filled with oxygen was reversed in a 
basin containing mercury. A cupel placed at the 
extremity of a little column received the diamond, 
upon which the sun's rays were concentrated by 
means of a burning-glass. 

The diamond disappeared; and it was proved 
that the glass, which at the commencement of the 
experiment had contained no trace of carbonic acid, 
contained a great quantity after the disappearance 
of the diamond. The diamond then contained 
carbon as one of its elements. Davy did not remain 
satisfied with this. 

By analogous experiments he showed that the 
combustion of the diamond in oxygen produced 



COMPOSITION OF DIAMOND. 8 1 

carbonic acid only; the diamond, then, must be com- 
posed of carbon and nothing else. 

Certain doubts still lingered upon this point, but 
they were dispelled by the publication in 1841 of 



■ 


H 




Is 


BslU^ ''"imiiiimnHMB^I 


■■ ■■ '^^^^WWj 



Fig. 31. — Combustion of the Diamond hy Lavoisier. 

the grand work of MM. Dumas and Stass upon 
the equivalent of carbon. 

In their experiments these two savants burned a 
great number of diamonds, but they corrected an 
error the maintenance of which would have been 
a veritable calamity to science. The capital impor- 



$2 PRECIOUS STONES. 

tance of the results obtained by MM. Dumas and 
Stass completely justified the use of such ex- 
ceptional fuel. 

It is very probable that the absolutely pure dia- 
mond consists exclusively of carbon ; but perfectly 
pure diamonds are very rare. All those burned by 
MM. Dumas and Stass left a residuum or ash, if 
we may call it so, sometimes in the form of a 
spongy network of a reddish-yellow colour, some- 
times as crystalline particles of a straw-yellow 
colour, sometimes as colourless and crystalline frag- 
ments. This residuum varied from -g^ to ^o^oo of 
the weight of the diamond employed. 

It used to be believed that the diamond could be 
consumed only with great difficulty. This error is 
corrected by one of the most fascinating experi- 
ments of chemistry. It was first performed by M. 

Morren, senior of the faculty of sciences 

at Marseilles. 

He took a wire of platinum, and by 

means of a little cone of wood gave it 

the shape represented by Fig. 32. 

He then fixed the upper end of the 

wire in a cork, and placed in the little 

receptacle the diamond to be burned. 

A phial filled with oxygen was at hand. 

By aid of a blowpipe the temperature of 
the diamond and its support was elevated to white 



COMPOSITION OF DIAMOND. 



S3 



heat, and then was plunged quickly into the phial 
of oxygen (Fig. 33). The diamond immediately 
kindled, and continued to burn with a steady glow 
infinitely more vivid than that which could have 
been obtained from any other variety of carbon. 




F'S- 33. — Combustion of the Diamond in Oxygen. 



M, Morren has also proved that the diamond 
burns in layers : for if the combustion is arrested at 
any period, the special system of crystallization is 
still regularly displayed. 

This is a very important point, since it excludes 
all idea of fusion for the diamond. 



8^4 PRECIOUS STONES. 



CELEBRATED DIAMONDS. 

It is from Asia, that cradle of luxury and splen- 
dour, that most of the diamonds that have become 
famous have been derived. 

Tavernier gives a minute description of the dia- 
monds of Aurengzebe, at whose court he was 
favourably received, and whose jewels he was per- 
mitted to inspect and weigh. 

"The first stone," he writes, "that Akel-Kau 
placed in my hands was a great diamond cut as a 
rose, very high on one side. It had a slight notch 
on one of its edges, and a small flaw within. It was 
of the first water, and weighed 280 carats." When 
brought from the mine of Colore, near Golconda, it 
weighed 78yj4 carats, but had several flaws. Hor- 
tensio Borghis, a Venetian, was employed to cut it, 
and the work nearly cost him his life ; for the king 
accused him of having spoiled the diamond, and 
only allowed him the privilege of retaining his head 
on the payment of ten thousand rupees. This dia- 
mond is believed to be the same as that which now 
belongs to Queen Victoria, and is known as the 
Koh-i-noor. Its history will be given below. 

"After having fully examined this beautiful 
stone," continues Tavernier, "and having returned 
it to the hands of Akel-Kau, he showed me another 



CELEBRATED DIAMONDS. 85 

diamond, finely formed, and of the first waiter, with 
three table-cut diamonds, two clear, and one having 
little black points. Each one of these weighed 
from 48 to 50 carats ; and the first 54^ carats. He 
then showed me a trinket consisting of twelve dia- 
moffds all roses, and each one weighing from 13 to 




Fig. 34. — Diamond of the Rajah of Mattan. 

14 carats. In the midst was a heart-shaped rose, 
of first water, with three little flaws: this rose 
weighed 35 carats." 

One of the most celebrated diamonds is that of 
the Rajah of Mattan, in Borneo. It was found on 
that island, and weighs 318 carats.^ It is shaped 

• Other accounts make the weight of this diamond 367 carats. 



86 



PRECIOUS STONES. 



like a pear, and of the dimensions shown in 

Fig. 34- 

This diamond is considered by the people of 
Borneo as a kind of palladium to which the 
destinies of the empire are attached. They attri- 
bute to it the miraculous power of curing all diseases 




-\}si^ 



Fig- 35. — The Nizam. 



/ 



by means of the water in which it has been dipped. 
On one occasion, according to Jamieson, the gover- 
nor of Borneo offered for it $150,000, two large war- 
brigs with their guns and ammunition, a certain 
number of guns, and a quantity of powder and shot. 
But the rajah refused to part with it. 

India has in its possession another famous dia- 
mond, the Nizam (Fig. 35), a rough diamond 
weighing 340 carats, and estimated at $930,000. 

One of the most celebrated diamonds in the 



CELEBRATED DIAMONDS. 



87 



world is the Regent or Pitt diamond. Its brilliancy 
and proportions are considered matchless, and it is 
also of considerable size. It was found in the mine 
of Parteal, forty-five leagues south of Golconda, and 
weighed in the rough state 410 carats. Two years 
and ^3,250 were spent in cutting it into a brilliant 




Fig. 36.— The Regent. 

— a process which reduced it to 137 carats, but the 
cutting is perfect. 

The usual account given of this diamond is, that 
it was bought at Madras by the grandfather of the 
first Earl of Chatham, when he was commander of 
Fort St. George ; that he paid $60,000 for it, and 
that it was bought in 17 17 for $648,000 by the 



88 PRECIOUS STONES. 

Duke of Orleans, when regent of France during the 
minority of Louis XV. 

A very different story, however, is told by Saint- 
Simon, who professes to speak of his own personal 
knowledge. 

He says that the diamond was stolen by a per- 
son employed in the diamond mines, who escaped 
to Europe with it, and after showing it to several 
princes, and among the rest the King of England, 
passed over to Paris and showed it to the somewhat 
notorious Law. Law proposed to the regent that 
it should be bought for the king, but the state of 
the finances was such that the duke hesitated to 
spend such a large sum in that way. Saint-Simon 
lent his influence in favour of the purchase, repre- 
senting that the diamond was peerless in Europe, 
and would well become the crown of France, and 
that the purchase of it would shed glory on the 
regency of the duke. The latter at last consented, 
and the diamond was bought for $384,000, the seller 
receiving also the fragments resulting from the 
cutting, with interest on the price until the whole 
was paid. 

From that time the Regent became identified 
with the fortunes of France, and a chapter of his- 
toric details belongs to its career. It has passed 
through many revolutions, and it has passed — very 
literally — through many hands; . for in the days 



CELEBRATED DIAMONDS. 89 

that followed the fall of Louis XVL, the Regent, 
carefully chained and guarded by gendarmes, was 
exposed to the people of Paris; and any half-starved 
workman who chose might . hold this symbol of 
royal splendour and epitome of twelve million francs 
for a few moments in his brown hand. 

The Regent — pawned to the Batavian govern- 
ment by Napoleon I. — stolen by robbers, and its 
hiding-place revealed at the gate of death by one 




Fig- 37- — Empress Eugenie. 

of the reckless band, and mounted in the state 
sword of the first Napoleon — finally glittered in the 
imperial diadem, through the palmy days of 
Napoleon III. 

Another beautiful diamond is the Empress Eu- 
genie. It is cut as a brilliant, and weighs 5 1 carats. 

A third famous diamond, belonging for some 
time to France, is the Sancy. Its history is not 
quite certain. According to some authorities it 
was brought by an ambassador from Constanti- 



^o 



I>RECIOUS STONES. 



nople; according to others, it ornamented the hel- 
met of Charles the Bold, who lost it at the battle of 
Granson. It was found by a Swiss soldier, who 
sold it to a priest for two francs; it disappeared 
then for some time, until, in the year 1589, King 
Anthony of Portugal pledged it among other 
stones to De Sancy, then treasurer of the King 
of France, who retained it by paying 100,000 livres 




Fig. 38. — The Sancy. 

(coinage of Tours). Henry III., after a lapse of 
time, borrowed it for the purpose of pledging it to 
the Swiss government; but the servant who was 
carrying it to the king disappeared, and was not 
heard of for some time. At last it was discovered 
that he had been assassinated in the forest of Dole, 
and buried by the care of a charitable cure in the 
cemetery of a village. " Then," said the Baron de 
Sancy, " my diamond is not lost." In fact the gem 
was found in the stomach of the servant, whose 



CELEBRATED DIAMONDS. 9I 

fidelity had given him at the last moment the pre- 
sence of mind to swallow it. 

According to the inventory of 1791 the Sancy 
weighed 33Yf carats. It excited especial interest 
from the peculiarity of its cutting. 

■In 1792 the Sancy once more disappeared, and 
was found by the police of Paris, through an anony- 
mous letter, in the Champs Elysees. It is now in 
Russia, and is valued at what M. Helphen con- 
siders an exaggerated price, $186,000. 

The crown-jewels of France, including the Re- 
gent and the Sancy, contained in 1774, 7482 
diamonds. This magnificent collection was stolen 
in 1792. 

The collection of Napoleon I., gathered from 
every part of Europe, was superior to the old col- 
lection, but inferior to the one subsequently made, 
which contained 64,812 diamonds, in 1832, valued 
at $3,887,848. After that time there was again an 
increase in the number of the French jewels, in- 
cluding the beautiful Empress Eugenie. 

Within a year, according to statistics of 1872, 
the Bonaparte family alone have thrown upon the 
market diamonds to the amount of $1,210,000. 

Brazil, rich in mines of precious stones, would 
naturally be supposed to possess valuable jewels; 
and in fact the crown diamonds of this empire are 
valued at more than $18,600,000. 



92 PRECIOUS STONES. 

Among the principal diamonds is that which, cut 
in a pyramid, adorns the handle of the cane of 
John VI., and is estimated at $162, 1:92. Brazil has 
furnished also the twenty diamonds which form the 
twenty buttons of the doublet of ceremony of 
Joseph I., each one of which is valued at $23,250; the 
whole costume representing a sum of $465,000. 

But the marvel among these productions of Bra- 
zil is the Star of the South. This extraordinary 
diamond was found in 1853 in the mines of Boga- 
gan, by a poor negress. The rough diamond 
weighed 257^ carats. It has been purchased by 
M. Helphen. 

This beautiful diamond has now been cut. It is 
of an irreproachable purity, transparent, and taking 
by refraction a lovely rose tint. 

The Star of the South was cut at Amsterdam 
in the establishment of M. Coster ; and no better 
example could be given of the difference between a 
rough diamond and one that has been cut, than is 
presented by Fig. 39, in which the different views 
of the Star of the South, in its rough state, are 
taken from drawings made by the illustrious miner- 
alogist M. Dufrenoy. Figures are also given of the 
diamond as it now appears. 

Among the diamonds found in Brazil are three 
famous stones belonging to the crown of Portugal.. 

The first is called the King of Portugal's dia- 



CELEBRATED DIAMONDS. 



93 



mond. It was found in a place called Cay-de- 
M^rin, near the little river of Malhoverde. Mawe 




Fig- 39 — Star of the South, before and after cutting. 

says that it weighs 1680 carats. And in Brazil its 
value is estimated at 11,395,000,000. Only — it has 



94 PRECIOUS STONES. 

been suggested, that this diamond is a topaz, in 
which case the millions vanish. 

No one is allowed to behold this diamond, which 
is still in the rough. And since the question of its 
nature is not tested, it may be presumed that the 
test is withheld for good reasons. 

Of the value of the two other famous diamonds 
of Portugal there is no doubt. One weighs 215 
carats, the other is flatter and weighs a little less. 
These beautiful stones were found by three men 
who were banished to the province of Minas Geraes, 
and who bought their freedom with them. 

The crown of England is very rich in beautiful 
diamonds; its chief treasurers the famous Koh-i- 
noor, or " mountain of light." 

The history of this stone is obscure, but, as al- 
ready mentioned, it is believed to be the same gem 
as that described by Tavernier among the jewels of 
Aurengzebe. According to a Hindu legend it was 
worn by one of the heroes of the Indian epic poem 
the Mahabharata, and it would therefore have a 
history extending backward about 4000 years. 
Coming down to later times we find it in possession 
of Vikramaditya, rajah of Ujayin, 56 B.C.,* from 
whom it passed to his successors, the rajahs of 
Malwa, and latterly to the sultans of Delhi, when 
Malwa fell into their possession. Its later history 
is given by Mr. Hunt as follows: — "Nadir Shah, 



CELEBRATED DIAMONDS. 95 

on his occupation of Delhi in 1739, compelled Mo- 
hammed Shah, the great-grandson of Aurengzebe, 
to give up to him everything of value that the im- 
perial treasury possessed ; and his biographer and 
secretary signifies a peshkash or present by Mo- 
hammed Shah to his conqueror of several mag- 




Fig. 40. — The Koh-i-noor before re-cuttiiig. 

nificent diamonds. , According to the family and 
popular tradition Mohammed Shah wore the Koh- 
i-noor in front of his turban at his interview with 
his conqueror, who insisted in exchanging turbans 
in proof of his regard. However this might have 
been, we need have little doubt that the great dia- 



96 PRECIOUS STONES. 

mond of Aurengzebe was in the possession of Mo- 
hammed Shah at the time of the Persian invasion ; 
and if it was it most certainly changed masters^ 
and became, as is universally asserted, the property 
of Nadir Shah, who is also said to have bestowed 
upon it the name of Koh-i-noor. After his death 
the diamond, which he had wrested from the unfor- 
tunate representative of the house of Timur, became 
the property of Ahmed Shah, the founder of the 
Abdali dynasty of Kabul, having been given to him, 
or more probably taken by him, from Shahrikh, 
the young son of Nadir. The jewel descended to 
the successors of Ahmed Shah, and when Mr. El- 
phinstone was at Peshawur was worn by Shah 
Shujah on his arm. When Shah Shujah was driven 
from Kabul he became the nominal guest and 
actual prisoner of Runjet Sing, who spared neither 
importunity nor menace, until, in 1813, he com- 
pelled the fugitive monarch to resign the precious 
gem, presenting him on the occasion, it is said, with 
a lakh and 25,000 rupees, or about $60,000. Run- 
jet was highly elated by the acquisition of the dia- 
mond, and wore it as an armlet at all great festivals. 
When he was dying an attempt was made by per- 
sons about him to persuade him to make the dia- 
mond a present to Jaganath, and it is said that 
he intimated assent by an inclination of his head. 
The treasurer, however, whose charge it was, re- 



CELEBRATED DIAMONDS, 97 

fused to give it up without better warrant, and 
Runjet dying before a written order could be 
signed by him, the Koh-i-noor was preserved for a 
while for his successors. It was occasionally worn 
by Rhurreuk Sing and Shu Sing. After the mur- 
da» of the latter it remained in the Lahore treasury 
until the supercession of Dhulip Sing and the 
annexation of the Punjaub by the British govern- 
ment (1849), when the civil authorities took pos- 
session of the Lahore treasury, under the stipu- 
lations previously made that all the property of the 
state should be confiscated to the East India Com- 
pany, in part payment of the debt due by the 
Lahore government, and of the expenses of the 
war; it was at the same time stipulated that the 
Koh-i-noor should be presented to the Queen of 
England. Such is the strange history of certainly 
one of the most extraordinary diamonds in the 
world. After the Company became possessed of 
the gem it was taken in charge by Lord Dalhousie, 
and sent by him to England in custody of two 
officers." 

When the Koh-i-noor was brought to England 
it weighed i86tV carats, and had the form shown 
in Fig. 40. It was exhibited in this state at the 
Great Exhibition of 185 1, and was valued at about 
$700,000. At that time it was merely surface cut, 

and was also disfigured with several flaws, so that 

7 



98 ' PRECIOUS STONES. 

re-cutting seemed advisable ; and it was decided to 
give it the form of the brilHant. The cutting was 
begun on July i6, 1852 — the Duke of Wellington 
being the first person to place it on the cutting 
mill — and was finished Sept. 7, thus occupying in 
all thirty-eight days of twelve hours each. It had 






Fig. 41. — The Koh-i-noor after being re-cut 

now the form represented in Fig. 41, its weight 
being reduced to 122^ carats. In cutting it some 
parts were found to be very much harder than 
others. Though so much reduced in weight by 
this operation the Koh-i-noor has been much im- 
proved in brilliancy and effect. 

Besides the Koh-i-noor, and a great number of 



CELEBRATED DIAMONDS. 99 

fine pearls, the crown of Queen Victoria contains 
497 diamonds, of which the value is estimated at 
more than $372,000. 




Fig. 42. — The Pigott. 

Another well-known diamond is the Pigott, which 
was brought from the Indies by Lord Pigott. Its 
weight is 81K carats. It was sold by lottery in 
1 80 1 for the sum of $139,500. Later it became the 
property of the Pasha of Egypt, who paid for it an 
equal sum. Fig. 42. 




Fig. 43. — The Nassac 

The Nassak or Nassac is a diamond of a triangular 



lOO 



PRECIOUS STONES. 



form, with curved facettes, belonging to the Mar- 
quis of Westminster, who had it cut into its present 
form. It weighs 78^ carats, and is estimated at 
about $148,000. 

The country that is most rich in diamonds at 
present is Russia. 

Besides special collections of diamonds in the 
treasury of this empire, there are three crowns of 
which they form the sole jewels. The first, that of 
Ivan Alexiowitch, contains 881 ; that of Peter the 
Great, 847; and that of Catherine the Great, 2536. 




Fig. 44.— The Orlow. 



Among the large diamonds in Russia the most 
remarkable is the Orlow. It weighs 193 carats. 
It has, as is shown by Fig. 44, the form of a half 
egg. It is one of the ornaments of the imperial 
sceptre. 

This beautiful diamond was originally from India. 
It formed for a century and a half one of the eyes 




Fig. 45.— Surface of Roses compared to their Weight. 



CELEBRATED DIAMONDS. 



103 



of the famous idol of Serringham in the temple of 
Brahma ; the other eye was a diamond of the same 
order. 

At the commencement of the eighteenth century 
the idea seized a French soldier of one of the French 
garrisons in India to steal the eyes of this cele- 
brated idol. He pretended to be inspired with a 
wonderful zeal for the Hindu religion, and gained 
to that degree the confidence of the priests that 




Fig. 46.— The Shah. 

they confided to him the care of the temple. He 
chose his time, and one stormy night carried off 
one of the diamonds; the other could not be 
forced from the socket. He fled to Madras, where 
he sold the stolen treasure to a captain of the 
English navy for $9300. Conveyed to England it 
was bought for $55,800 by a Jewish merchant, 
who sometime after sold it to Catherine H. for 
$418,500, and a pension for life of f 18,600. 

It was this famous stone that suggested Wilkie 
Collins' novel "The Moonstone." 



I04 PRECIOUS STONES. 

Another beautiful Russian diamond is called the 
Shah : it belonged pnce to the ancient monarchs of 




Fig. 47.— The Polar Star. 

Persia. It is of very excellent water, and weighs 95 
carats. Fig. 46 shows the peculiar form of this 
beautiful stone. 

The third great Russian diamond is the " Moon 
of the Mountain." It was bought for 50,000 piastres 




Fig. 48. — ^The Grand-duke of Tuscany. 



of an Afghan chief by an Armenian merchant 
named Schafnass, who kept it for twelve years, and 



CELEBRATED DIAMONDS. 



105 



then sent it by his brother to Amsterdam, where, 
after a long negotiation, it was bought by Russia 
for $334,800 and a patent of nobility. 

Russia possesses also a superb diamond, the Polar 
Star, cut as a brilliant, and weighing 40 carats. It 
belongs to the Princess Youssoupoff. Fig 47. 

The finest diamond owned by Austria is the 
Grand-duke of Tuscany. It is a little yellow, and 
is cut to represent a star of nine rays. Fig. 48. 

This diamond belonged to Charles the Bold, who 
lost it at the battle of Granson. Found by a 
soldier, it was sold by a Genoese merchant to Ludo- 
vic Sforza, duke of Milan, It became afterwards 
the property of Pope Julius IL, who presented it to 
the Emperor of Austria. It weighs 1^9/4 carats. 





5H 


M 




1 


1 



Fig. 49.~The Pasha of Egypt. 



Egypt possesses a very beautiful brilliant of 40 
carats, which bears the name of the Pasha of 
Egypt. It cost $136,200. 

In Holland there is a diamond ot 36 carats, esti- 



io6 



PRECIOUS STONES. 



mated at $48,360 ; and one in the treasury of 
Dresden that weighs 31^ carats. 

A black diamond was sold by M. Bapst to Louis 
XVIII. for the sum of $4464, but it was never de- 
livered. Its colour was a very dark brown, and it 
had a remarkable lustre. 




Fig. 50. — The Blue Diamond of Mr. Hope. 

A precious stone without a rival is the blue dia- 
mond of Mr. Hope. Its weight is 44^ carats, and 
its colour is the blue of the most beautiful sapphire, 
added to an adamantine lustre of the utmost bril- 
liancy. It was purchased for $83,700, but com- 
petent judges declare that it is worth more. 



ENGRAVING UPON THE DIAMOND. 



Notwithstanding its wonderful hardness, the dia- 
mond has been engraved. 

In the Paris Exhibition of 1867, in the Italian 
section, an engraved diamond was exhibited. It 




Fig. 51.— Surfaces of Brilliants compared to their weight. The vertical lines 
indicate the thickness of the stone. 



CELEBRATED DIAMONDS. IO9 

was engraved in the sixteenth century by Jacopo or 
Como da Trezzo ; and it was set in a unique cylin- 
drical ring : of gold, by aid of a movable collet 
upon pivots. 



PART IV. 

Sapphire. Ruby. Balas Ruby. Spinel Ruby. Topaz. Emerald, 
Beryl. Aquamarine. Cymophane. Turquoise. 

" What wonder then, if fields and regions here 
Breathe forth elixir pure, and rivers run 
Potable gold, when with one virtuous touch 
Th' arch-chemic Sun, so far from us remote, 
Produces, with terrestrial humour mix'd 
Here iu the dark, so many precious things. 
Of colour glorious, and effects so rare ? " 

Every one knows that common substance called 
c/ay, which is so easily mixed into a paste with 
water. But every one does not consider perhaps 
what an important part in agriculture and industry 
this familiar substance performs. 

All soils that are of value for the production of 
vegetables contain clay. The principal element of 
this substance — alumina — is necessary to the de- 
velopment of plants; and its presence is necessary 
to retain the humidity of soil that is indispensable 
to vegetable life. 

To indicate the importance of clay in the indus- 
trial world it is only necessary to say that tiles, 
bricks, pottery, from the coarsest kind to the finest 

; 



COMPOSITION. 1 1 1 

Sevres ware, are almost exclusively formed of this 
substance. 

And what is clay.'' 

To answer this question categorically is impos- 
sible, because there are comprehended under that 
nauie a multitude of mixtures, whose composition 
is extremely variable; but the only fact important 
for us to know here is that the principal constituent 
element of clay is alumina. 

In these modern times industry has been en- 
riched by an important conquest, aluminium, that 
new metal which, whether used alone or in com- 
bination with other metals, lends itself with com- 
plete success to the manifold wants of the industrial 
arts. It is a discovery and creation for which our 
epoch is indebted to the French chemist M. Henri 
Sainte-Claire Deville. 

If this metal is combined with the oxygen of the 
air, the metal disappears, and is transformed into 
the rust of aluminium; exactly as the brilliant and 
metallic iron is transformed into iron rust under 
the same conditions; only that aluminium rust is 
white instead of red. This white rust is pure 
alumina. 

Now this alumina exists in a prodigious quantity, 
not only in vegetable mould, but also in a large 
portion of the rocks of our globe. Generally it is 
mixed with iron rust, which gives it a red colour, or 



112 PRECIOUS STONES. 

it may be with other substances ; but it now and 
then occurs in absolute purity; and it is always 
possible to extract pure alumina from any kind of 
clay. 

If we ask now what is the composition of the 
precious stones whose names figure at the head 
of this chapter, we are answered — they are formed 
of alumina nearly pure. Besides this they contain 
only some faint traces of foreign matters, generally 
of the oxide of iron. 

Notwithstanding the minute quantities, these 
foreign matters are very important, because it is to 
their union with alumina that the precious stones 
we are considering owe their remarkable colour, and 
consequently a great part of their commercial 
value. 

But if the ruby, the sapphire, and kindred gems, 
are formed almost exclusively of alumina, we must 
hasten to add that this alumina is crystallized, for 
in this fact is comprehended the cause of the enor- 
mous distance which separates the alumina of the 
soil around us from the alumina of which precious 
stones are composed. 

CORUNDUM. 

Modern mineralogists have given the single name 
corundum to all the minerals consisting of crystal- 



CORUNDUM. 



113 



lized alumina almost pure, without regard to the 
colour of these minerals. 

Corundum comprehends three varieties : the hya- 
line corundum, the laminated corundum, and the 
granular corundum. The first variety comprehends 
the precious stones. 

The primitive form of the crystals of corundum is 
the six-sided prism (Fig. 52), but the most general 
form of the hyaline corundum is the dodecahedron 
(Fig. 53), with faces formed of isosceles triangles. 





Fig. 52.. — Primitive form of 
Corundum. 



Fig- S3- — Most common form 
of the Corundum. 



Nearly all the hyaline corundums susceptible of 
being employed in jewelry are brought from Pegu. 
The price of these stones is very high. It is not a 
rare occurrence for the price of the ruby to exceed 

8 



114 PRECIOUS STONES. 

that of the diamond. At an auction of precious 
stones from the cabinet of M. Dree a very beautiful 
diamond of 8 grains (2 carats) was sold for $148, 
while a ruby of the same weight brought $186. At 
the same sale the price of a ruby of 10 grains 
reached $2604. The value of the ruby and that of 
precious stones generally varies with their richness 
of tone. 

When the corundum is perfectly colourless it 
possesses a brilliancy so vivid that in some circum- 
stances it may pass for a diamond. It may be dis- 
tinguished from the latter by its inferior hardness, 
its smaller specific gravity (3*5, while that of the 
diamond is 3*9), and by having double refraction. 

According to the tints which the corundum pos- 
sesses, it bears different names, and represents 
variable values. 

Names of the corundums according to their 
colour : — 

White Sapphire, ' Colourless. 

Oriental Ruby, ... Crimson red. 

Oriental Ruby (variety), Rose red. 

Oriental Sapphire, Azure blue. 

Indigo Sapphire, Indigo blue. 

Oriental Amethyst, Violet. 

Oriental Topaz, Yellow. 

Oriental Emerald, Green. 

THE RUBY. 

There exists but one true ruby, the oriental 
ruby. 



THE RUBY. 115 

The spinel ruby and the balas ruby must be care- 
fully distinguished from this valuable gem, as 
neither in nature nor composition do they resemble 
the oriental ruby, 

"The oriental ruby," says Babinet, "ranks first 
for, price and beauty among all coloured stones. 
When its colour is of good quality it has the vivid 
tint of arterial blood (a tint called ' pigeon's blood ' 
in commerce), or of the very centre of the red ray 
in the solar spectrum. It is the perfect red of the 
painter's palette, without any mixture of violet or 
of orange. Several of the reds in the stained glass 
of our ancient cathedrals, when the daylight pours 
through them, give an idea of this brilliant 
colour. 

" The ruby is extremely hard ; and after the 
sapphire, which surpasses it a little in this respect, 
it is the hardest of precious stones, always ex- 
cepting the diamond, to which nothing can com- 
pare. M. Charles Achard, the highest authority 
in France in all that concerns the traffic in coloured 
stones, remarks that weight has not the same effect 
in their case as in that of the diamond. Every dia- 
mond, from the very smallest specimen upwards, 
has its value like gold or silver, according to weight; 
but in the case of rubies and other gems the little 
specimens have hardly any value ; and these stones 
only begin to be appreciated at the moment when 



Il6 PRECIOUS STONES. 

their weight withdraws them from the common 
ruck, and assures at once their rarity and high price. 
When a perfect ruby of 5 carats enters the market 
a price will be offered for it double the price of a 
perfect diamond of the same weight ; and if a ruby 
reaches the weight of 10 carats it will bring triple 
the price of a diamond of the same weight (from 
three to four thousand dollars), 

" I have seen many collections of amateurs, visited 
and consulted many lapidaries, and everyone admits 
that a perfect ruby is the most rare of all the pro- 
ductions of nature. The tint of the ruby is as 
admirable by artificial light as by the light of day." 

The precious stone called the carbuncle by the 
ancients is the same as our modern ruby. 

The most fantastic qualities were formerly as- 
cribed to these wonderful stones. The carbuncle 
served to furnish light to certain great serpents or 
dragons when old age had enfeebled their eyes; 
they constantly carried these magical stones be- 
tween their teeth, only dropping them when it was 
necessary to eat and to drink. And according to 
St. Epiphanius the carbuncle has not only the pro- 
perty of shining brilliantly in darkness, but its light 
is of a nature so extraordinary that nothing can 
arrest it; so that it shines, for instance, through 
vestments with undiminished fire. 

At the same time that it is averred that the car- 



SPINEL RUBY AND BALAS RUBY. II7 

buncle of the ancients included our oriental ruby, it 
is equally certain that this name was appHed to all 
red stones — oriental ruby, spinel ruby, garnets, &c. 
— in the same indiscriminate manner as the East 
Indians apply the name ruby to all coloured pre- 
cioHfS stones. 

When Pegu, that fatherland of rubies, was an- 
nexed in 1852 to the English possessions, it was 
believed that Europe would receive at least a part 
of the rubies that had been for so many centuries 
locked up in that country. That hope has been 
completely disappointed. It is not even certain 
that the mines there continue to be worked. It 
would seem also that the regions where rubies exist 
are extremely dangerous to approach on account of 
lions, tigers, and serpents. To be sure, it is very 
probable that merchants in rubies designedly exag- 
gerate these dangers to delay competition ; but it is 
certain that this part of Asia is very little known, 
and the known condition of the island of Borneo 
seems to justify the opinion. 

SPINEL RUBY AND BALAS RUBY. 

In connection with the oriental ruby two other 
productions of quite a different nature must be 
described, namely, the spinel ruby and the balas 
ruby. 

The first is generally a very vivid poppy red; 



Il8 PRECIOUS STONES. 

the second of a violet rose, or a vinegar rose ; but 
there is no absolute rule for their colour, since Pegu 
furnishes white and violet-white spinels ; and speci- 
mens have been brought from Aker in Sudermania 
which are of a bluish gray. 

Spinels are brought also from Ceylon and other 
oriental countries; everywhere they are found in 
the beds of torrents, in the midst of alluvial 
deposits. 

The primitive form of the crystals of spinel ruby 
is octahedral, like that of the diamond; this charac- 
teristic suffices to distinguish immediately the spinel 
or balas ruby from the oriental ruby, since the 
crystals of the latter present the form of six-sided 
prisms. 

The composition of the spinel ruby and balas 
ruby differ essentially from that of the oriental ruby, 
the latter being a corundum formed nearly ex- 
clusively of alumina, while in the former only 70 
parts in 100 are alumina, and the remainder chiefly 
magnesia. The colour, moreover, is in part due to 
the oxide of chromium, a substance of which the 
oriental ruby does not contain the slightest trace. 

In a scientific point of view the balas ruby does 
not differ from the spinel ; and many special works 
confound the two completely. But in commerce 
the stone called Balas has a value very much below 
that of the spinel. 



CELEBRATED RUBIES. 



119 



In the inventory of the crown jewels of France 
the price of balas rubies is four or five times less 
than that of spinels. 



CELEBRATED RUBIES. 



•The largest ruby known is one mentioned by 
Chardin as having been engraved with the name of 
Sheik Sephy. 




Fig. 54- — King of Persia's Ruby. 

Tavernier gives a figure of another celebrated 
ruby in the possession of the King of Persia: it is 
reproduced in Fig. 54. Its weight was 175 carats. 

A third, belonging to the King of Visapur, had 
the figure and dimensions of Fig. 55. It was cut, 
as will be seen, en cabochon, and it had been bought 
in 1653 for nearly %\i,Z6^. 



120 



PRECIOUS STONES. 



A fourth, seen by Tavernier in India, is repre- 
sented by Fig. 56. 

According to the judgment of Tavernier it was 
of secondary beauty; yet this celebrated traveller 
offered $11,160 to the diamond merchant who pos- 
sessed it, but could not obtain it at that price. 

A ruby possessed by Gustavus Adolphus, and 
presented by him to the Czarina in 1777, at the 





F'g- 55- — Ruby of the King of Visapur. 



Fig. 56. — Indian Ruby. 



time of his journey to St. Petersburg, was the size 
of a small hen's egg. 

A ruby in the French crown, adorning the order 
of the golden fleece, is in the form of a dragon. 

Finally, it is seen from the inventory of 179 1 that 
France then possessed eighty-one oriental rubies, 
estimated at $6138. 

In England the ruby is especially prized; and 
some beautiful and very valuable stones are in the 



THE SAPPHIRE. 121 

hands of the nobility. In America it is less highly 
estimated. 

ENGRAVING UPON RUBIES. 

The ancients seldom engraved the ruby. Pliny 
ascribes this fact to the singular reason that seals 
made of this stone carried away the wax. 

The excessive hardness of the ruby, its costli- 
ness, and the great rarity of specimens proper for 
engraving are, without doubt, the true reasons which 
prevented the ancients from engraving it; the im- 
possibility, moreover, of polishing the cavities made 
in this substance may have occasioned the fault 
which Pliny has ascribed to ruby signets. 

In the Odescalchi museum the design of an en- 
graved ruby represents Ceres standing with an ear 
of corn in her hand. 

Another engraved ruby represents a bearded head, 
supposed to be that of a Greek philosopher. This 
ruby is cut in the shape of a heart, and formed a 
part of the collection of the Duke of Orleans. 

Both these engraved rubies are spinel rubies. 

THE SAPPHIRE. 

The word sapphire is derived from the Syriac 
saphilah, a name which indicates the same stone in 
this Eastern tongue. 



122 ■ PRECIOUS STONES. 

In commerce there are four different stones that 
bear the name of sapphire : — 

Oriental Sapphire. I Sapphire of Puy. 

Brazilian Sapphire. I Water Sapphire. 

The three first are corundums, and consequently 
true sapphires. The last is a coloured quartz, and 
a stone of but trifling value. 

The oriental sapphire has been known from 
earliest antiquity. It was one of the precious stones 
that had place in the breastplate of Aaron. To 
the ancients it was the gem of gems, the sacred 
stone par excellence. The Greeks dedicated it to 
Apollo. 

The first sapphires that reached Europe came 
from Arabia; later they were imported from Persia. 
At the present day they are found principally in 
Arabia and the Brazils; and the productions of both 
these countries are called oriental sapphires. 

There are certain sapphires, generally of a pale 
colour, which, when examined under the microscope, 
exhibit thread-like shafts directed towards the 
faces of the six-sided prism ; these threads are pro- 
duced by foreign substances, or by vacuities left 
among the molecules at the moment of their crys- 
tallization. The light reflected upon them forms a 
star of six rays, extremely beautiful and remarkable. 
Sapphires of this kind are called asteria sapphires^ 
or star sapphires. 



THE SAPPHIRE. 1 23 

The orientals have a deep veneration for the star 
sapphire; and M. D'Abbadie, in his travels in 
Africa, often commanded the respect of the natives 
by allowing a stone of this kind, which he always 
carried with him, to exhibit its magical beauty to 
th^r astonished eyes. 

A stone of a yellow-green tint, exhibiting a simi- 
lar phenomenon, is brought from Ceylon. It is 
called the Cafs Eye. Threads of white asbestos are 
inclosed within it, and the light is reflected from 
these in an intense manner. When this stone is cut 
en cabochon, a white band of light is seen floating in 
its interior, that changes position as the gem is 
moved before the eye. 

The sapphire of Puy is found in the rivulets of 
Expilly. Its colour varies from the deepest to the 
palest blue ; sometimes it passes to a reddish blue, 
or even to a yellowish green. Its composition is not 
always homogeneous; and the specimens which dis- 
play the finest water are those in which the tint 
verges upon green. They are found in ferruginous 
sand produced by decomposition of basaltic rocks. 

Fig. 57 is a view of the mountain of Expilly, 
where the sapphires of Puy are found. 

Among the celebrated sapphires we must mention 
above all that which figured in the famous " afiair 
of the necklace." 

Found in Bengal by a poor man who sold wooden 



12'4 PRECIOUS STONES. 

spoons, it was brought to Europe, and bought by 
the house of RaspoH at Rome. Later it became 
the property of a German prince, who sold it to 
Ferret, a Parisian jeweller, for $31,620. This beau- 
tiful stone, without blemish or faults of any kind, 
weighed 133^ carats. It formed afterwards part of 
the riches of the Museum of Natural History at 
Paris. 

This museum possesses another sapphire of ex- 
quisite beauty and exceptional size. It is oval, and 
measures two inches by one and a half. 

A very beautiful star sapphire belongs to one of 
the merchant princes of New York; and in England, 
among the jewels of Miss Burdett Coutts, are two 
magnificent sapphires estimated at $139,500. 

In the Hope collection — among several fine spe- 
cimens of this gem — is a stone called the "Mar- 
vellous Sapphire," which is blue by day and ame- 
thystine at night. This gem is said to have afforded 
the foundation of one of Madame de Genlis' stories. 

ENGRAVED SAPPHIRES. 

The ancients engraved the sapphire notwith- 
standing its extreme hardness. 

There is a beautiful sapphire among the crown 
jewels of Russia representing a female figure en- 
veloped in drapery. The stone is of two tints, and 



THE TOPAZ. 127 

the artist has skilfully used the dark tint for the 
woman and the light tint for the drapery. This 
gem formed part of the collection of the Duke of 
Orleans. 

The cabinet of France possesses in sapphire a 
ve*y remarkable intaglio representing the Emperor 
Pertinax. 

The marvel of this kind is an engraving by 
Cneius representing the profile of a young Hercules. 
It is in the Strozzi Cabinet at Rome. 

THE TOPAZ. 

The topaz, like its kindred precious stones, is 
divided into the occidental and the oriental. 

The oriental topaz should be in every respect 
carefully distinguished, because it is the only variety 
which is composed of alumina nearly pure. The 
others contain no more than 57 or 58 parts to 100 
of this substance. 

The topaz of the moderns is the chrysolite of 
the ancients. It is a corundum coloured by a 
slight quantity of the oxide of iron to a beautiful 
golden yellow. The topaz was originally found, as 
Pliny informs us, upon an island in the Red Sea, 
which, being often surrounded by fog, was so diffi- 
cult to find that the mariners named it Topaza (Gr. 
topazein, to guess). 



128 PRECIOUS STONES. 

This stone is now very rare; and when to the 
fineness of its quaHty it joins a soft clear colour 
with a satin-like lustre, it acquires a considerable 
value. But the topaz, however perfect, never 
reaches the price of a ruby or a sapphire, or even a 
fine emerald of equal dimensions. 

Occidental Topaz. — Stones thus designated are 
not corundums. They are of a more complex com- 
position; and the analysis of specimens brought 
from different localities proves that occidental 
topazes are not identical. They have for a long 
time been divided into four varieties : — 

Brazilian Topaz. I Mexican Topaz. 

Saxon Topaz. I Siberian Topaz. 

It should be remarked, however, that while the 
proportions of the elements differ in each of these 
varieties, their nature is the same. The occidental 
topaz is in all cases formed of alumina, silica, and 
fluoric acid. The presence of this last substance, 
found in no other precious stone, characterizes per- 
fectly the genus topaz in respect to chemical 
composition. 

The primitive type of crystals of topaz is the 
right rhomboidal prism (Fig. 58). 

Certain modifications occur in the form of these 
crystals, which, joined to their colour, enable a 
person to decide as to which of the varieties any 
topaz in question belongs. 




if 



THE TOPAZ. 129 

The Saxon topaz generally occurs in the form of 
a rhomboidal prism with a base; and its colour 
varies from an orange yellow to a straw yellow. 




Fig. 58.— Type of Crystal of Topaz. 



The Brazilian topaz exhibits most frequently a 
rhomboidal prism surmounted by a four-faced pyra- 





Fig. 59. — Saxon Topaz. Fig. 60. — Brazilian Topaz. 

mid, and its colour includes all the shades from 

orange yellow to wine yellow. 

9 



I30 



PRECIOUS STONES. 



The Siberian topaz is nearly always found in 
rhomboidal prisms, terminated by a ditetragonal 
pyramid; it is of a pale blue or green cast of colour, 
and sometimes occurs colourless, when it is much 
prized. Although in form of crystallization these 
Siberian minerals are really topazes, they approach 
very nearly by their tint and transparency to the 
aquamarine. 




Fig. 6i. — Siberian Topaz. 



Fig. 62.— Topaz of the Grand Mogul. 



A finely polished topaz belonging to the Grand 
Mogul was purchased at Goa for $50,500. It 
weighed 157^ carats, and was cut in the form 
represented by Fig. 62. 



ENGRAVING UPON THE TOPAZ. 

It was for a long time believed that the ancients 
never engraved this gem; but Caire mentions a 



THE AMETHYST. I3I 

topaz which he had had in his own possession 
weighing 29 carats, and engraved in Arabic 
with the motto, ^^ No one accomplishes but God!' 
It was probably an amulet, such as are worn by- 
orientals of the present day, and which are called 
by J:he Arabs gri-gri. 

Another celebrated engraved topaz represents 
Philip 11. and Don Carlos. It is a white topaz, en- 
graved by Jacopo da Trezzo. 

The house of Orleans had a very beautiful octa- 
gonal topaz engraved with a Mercury; and in 
Turin, in the Generosio collection, was a celebrated 
topaz intaglio, representing Victory enthroned in a 
chariot. 

THE AMETHYST. 

The oriental amethyst is a rare substance of 
magnificent lustre, and of a violet colour slightly 
tinted with red. 

The amethyst was the ninth stone in the breast- 
plate of Aaron; and in modern times it is the 
sacred stone which ornaments the cross and the 
pastoral ring of Catholic bishops. 

In the inventory of the crown jewels of France, 
1791, three superb oriental amethysts are mentioned, 
one of which weighed 13-^ carats, and was valued 
at $1116. 

But the greater part of the amethysts of commerce 



132 PRECIOUS STONES. 

are occidental amethysts. As their composition 
and value have nothing in common with the oriental 
amethyst they will be described elsewhere. 

ENGRAVING UPON THE AMETHYST. 

Ancient engravings upon amethyst are numerous. 
That which has been chosen as an example (Fig. 
6^) represents Antonia, the daughter of Mark 
Antony, and the wife of Drusus, a beautiful 




Fig. 63.— Antonia, wife of Drusus. 

princess, who, to use the touching language of 
Lenormant, "embodied in herself all the glory and 
the sorrow of her time." She is represented as the 
goddess Ceres, and carries a horn of plenty. In 
the National Library of France there is a mag- 
nificent work in amethyst, a profile (supposed to be 
Maecenas at an advanced age) engraved by Dios- 
corides, one of the four celebrated engravers 
mentioned by Pliny. 



EMERALD, BERYL, AQUAMARINE. 1 33 

Among the finest gems of the Pulsky col- 
lection is the head of a Syrian king upon a pale 
tinted amethyst, engraved with the artist's name 
NEAPKHS 

EMERALD, BERYL, AQUAMARINE. 

These three substances are, in a scientific point 
of view, very nearly identical ; but in commerce the 
value of the emerald is infinitely greater than that 
of the beryl and aquamarine. 

The emerald, when it possesses a green tint of a 
beautiful quality, and when it is entirely hyaline, is 
one of the most rare and precious of gems. On 
the contrary, when it appears in semi-transparent 
crystals of a watery green, it is quite common; 
indeed there are few granitic mountains where it 
has not been observed. 

The colour so remarkable in the emerald is 
due to a pretty large quantity, 8 to 9 parts in 100, 
of oxide of chromium. 

The fundamental form of crystals of emerald is 
the regular six-sided prism. As the side of the 
base nearly always equals the height, the faces of 
emerald crystals vary very little from a square. 

Another form which frequently occurs is the 
twelve-sided prism, which is derived directly from 
the primitive form by the modification of the six 
vertical edgfes. 



134 



PRECIOUS STONES. 



Like the other corundums the emerald is formed 
chiefly of alumina, but it has a peculiarity which 
renders it interesting to the chemist, since it con- 
tains a considerable proportion, 12 to 15 parts in 
100, of a rare body, glucina, the discovery of which 
is due to the illustrious chemist Vauquelin, 

It was for a long time believed that emeralds 
were always found in connection with granitic rocks; 





Fig. 64. — Fundamental Form of 
Emerald Crystals. 



Fig. 65. — Very common Form ol 
Emerald Crystals. 



but in 1848 M. Lewy, in the course of his travels in 
New Grenada, discovered that this opinion was 
erroneous. 

M. Lewy has shown in fact that the most beauti- 
ful specimens, those of the mine of Mouza, so far 
from existing in crystalline rocks, exist, on the con- 
trary, in the best defined secondary formations — in 
that division of the cretaceous formation to which 



BERYL AND AQUAMARINE. 1 35 

geologists have given the name of the neocomian. 
The fossils brought home by M. Lewy leave no 
room for doubt on this subject. 

Since the publication of the discovery of M. Lewy, 
MM. Nicaize and Montigny have found in the 
valley of the Harrach, in the province of Con- 
stantine (Algeria), a bed of emeralds, appertaining, 
like that of America, to the cretaceous formation, 

BERYL AND AQUAMARINE. 

The beryl and the aquamarine have the general 
composition and constitution of the emerald; but 
they differ from it in the absence of the oxide of 
chromium, which is in them replaced by the oxide 
of iron. The colour remains the same, but it is 
much feebler and less pure than in true emeralds. 

Beryl. — Among lapidaries and dealers in precious 
stones the beryl and the aquamarine constitute a 
well-defined group, altogether distinct from the 
emerald. With them the beryl is the oriental 
species of this group, and the aquamarine the 
occidental. 

For a long time the beryl was only known in 
India; afterwards it was met with in Arabia; and 
still later remarkable fragments of it were found in 
Russia, at Beresof, and in the environs of Lake 
Bolchoi. 



136 PRECIOUS STONES. 

Aquamarine. — The aquamarine is a stone of but 
trifling value, and yet it possesses a quality which 
should have prevented it from falling into its present 
low estimate; it does not lose its brilliancy in arti- 
ficial lights. 

" It is a curious spectacle," says Babinet, " to see 
a magnificent blue sapphire lose in the night all its 
glories, when a poor trinket of aquamarine not only 
retains all its effect, but even seems to gain brilliancy. 
The English are as fond of the aquamarine as the 
Spanish are of the topaz." 

The greater part of the aquamarines of commerce 
are furnished by Brazil. They are brought to 
Europe completely cut, and are sold by weight, but 
with extreme variations, since large and beautiful 
specimens are valued at from $75 to $95 the ounce, 
while the small ones hardly bring $5. 

Formerly the aquamarine was very abundant in 
Daouria, upon the frontiers of China, whence the 
Russian merchants took them in exchange for furs. 
They are now found in Siberia, the Ural Mountains, 
the Altai Mountains, &c. 

The emerald, so highly esteemed in our day, was 
not less valued by the ancients. Pliny describes it 
in the following terms : — 

"There is no colour so pleasing to the eye as that 
of the emerald. Whoever delights in the verdure 
of herb and leaf must enjoy infinitely more the con- 



BERYL AND AQUAMARINE. 1 37 

templation of emeralds, for no verdure can compare 
to theirs. They are the only stones that charm the 
eye without wearying it. Even when the eyes are 
fatigued by having looked too continuously on 
anything, the sight of an emerald soothes and 
strengthens them. Lapidaries can find nothing 
more refreshing for their tired eyes than the soft 
greenness of this stone. It loses its lustre neither 
in sun nor in shade, nor in artificial lights. It 
shines continually with the same soft glow." 

The emerald is mentioned several times in our 
translation of the Bible, but it is not certain that 
the word so translated really meant our emerald. 

Among precious stones there is not one that has 
formed the basis of such great exaggerations as the 
emerald. 

It is Herodotus who first describes those gigantic 
emeralds of which Theophrastus, Appian, and Pliny 
make later mention. 

Theophrastus relates that in the books of the 
Egyptians it was stated that a king of Babylon had 
sent to one of their kings an emerald four cubits 
long and three thick ; and that there was in Egypt, 
in a temple of Jupiter, an obelisk made of four 
emeralds, which nevertheless was forty cubits long, 
four cubits thick at some places, and two in others. 
He adds, also, that at the time when he wrote, there 
was yet to be seen at Tyre, in the temple of Her- 



138 PRECIOUS STONES. 

cules, an upright column, made of a single emerald. 
Appian, too, describes a colossal statue of Serapis, 
of the height of nine cubits, carved out of a single 
emerald. 

It is evident that these descriptions do not apply 
to our modern emerald. The productions they 
refer to were probably jasper and malachite; and, 
above all, vitreous masses artificially coloured by 
metallic oxides. 

REMARKABLE BERYLS AND AQUAMARINES. 

The finest beryl known is in the collection of 
Mr. Hope. It weighs nearly 6^ ounces, and cost 
$2325. It came from the mine of Cangayum, in the 
district of Coimbatoor, in the East Indies. 

A magnificent beryl surmounts the globe in the 
royal crown of England. It is perfectly clear, and 
of a lovely colour. It is cut in an oval form, and is 
2^3^ inches long, 1% m width, and i\ in depth. 

A celebrated aquamarine adorned the tiara of 
Pope Julius II. It measured 2-^ inches in length, 
and 2-| in thickness. Notwithstanding a slight 
flaw, it was considered by amateurs a very remark- 
able gem. 

Caire mentions an aquamarine which he had 
seen in London that weighed when cut 250 carats, 
and was valued by its possessor at $465. 



ENGRAVING UPON AQUAMARINE. 1 39 

In 1827, in the town of Mouzinskai'a in Russia, a 
superb specimen of aquamarine was found, valued, 
we are seriously told by the Russians, at $111,600. 

ENGRAVING UPON AQUAMARINE. 

A considerable number of both modern and 
ancient engravings are executed upon this stone. 
The gem represented in Fig. ^6 is a part of the 



Fig. 66.— Julia, daughter of Titus. 

collection of the National Library of France. It is 
the head of Julia, the daughter of Titus, and is 
signed by the artist Evodus. It was mounted ori- 
ginally with sapphires and pearls, and formed part 
of the decorations of a reliquary belonging to the 
abbey of St. Denis. 



I40 PRECIOUS STONES. 



ENGRAVING UPON THE EMERALD. 

The brittle texture of the emerald prevented it 
from being a favourite with engravers, consequently 
there are few engraved emeralds. 

There is a description of a beautiful composition 
executed in the middle ages upon this stone. It 
represented the soul led away by the pleasures. 

CYMOPHANE. 

The cymophane is formed like the emerald, of 
alumina and glucina. 

The cymophane of modern mineralogists is the 
oriental chrysolite, the chrysopal, and the chryso- 
beryl of the lapidaries. It is remarkable for its 
lively brilliancy, its polish, similar to that of the 
sapphire, and its warm gay tint. But its celebrity 
arises from its unique property of displaying blue 
reflections, with a milky tint that seems floating in 
its interior. This circumstance originated the 
name given to it by Haiiy, which signifies j^oatm£;' 
light. 

Crystals of cymophane are usually found in 
alluvial soils; in Ceylon and Brazil they occur in 
the same sands that furnish crystals of topaz, corun- 
dum, &c. — sands formed by the disintegration of 
ancient rocks. Fine specimens of cymophane have 



THE TURQUOISE. I4I 

recently been found in Connecticut and in the Ural 
Mountains. 

THE TURQUOISE. 

There are two species of oriental turquoise, the 
old rock and the new rock; and there is also an 
occidental turquoise. 

The terms old rock and new rock were applied to 
the turquoise in Persia. " The mine of turquoise," 
says Tavernier, "which furnishes the most beauti- 
ful stones, is three days' journey from Meshed, 
turning to the north-west after passing the large 
town of Nishabourg ; it is the old rock. The other, 
which is five days' journey, was discovered and 
worked more recently; it furnishes turquoises of a 
whitish blue, and almost valueless; it is the new 
rock." 

When Tavernier travelled in the East the King 
of Persia had already for a long time reserved for 
himself all the products of the old rock. He had 
ornaments made of them, which he presented to 
princes and kings. 

When the embassy was sent by the King of 
Persia to Louis XIV., among the many rich presents 
conveyed to ,the French monarch were a large 
quantity of turquoises. But all those who saw 
them were unanimous in deciding that they were 
noways remarkable, and by no means answered the 



142 PRECIOUS STONES. 

idea that had prevailed in Europe, of the much 
vaunted turquoises of the old rock. Perhaps the 
mine was already more or less exhausted. 

Oriental Turquoise. — This is another aluminous 
stone ; but alumina forms hardly more than half of 
its composition. 

The blue colour, so characteristic of the turquoise, 
is due, in great part at least, to a combination of 
phosphoric acid, copper, and iron, and probably also 
to water, of which it contains i8 or 19 parts in ICX). 

The turquoise harmonizes well with diamonds 
and pearls, and is frequently employed in jewelry. 
It is consequently an object of some commercial 
consideration ; but as it is pretty abundant it does 
not reach a high price, unless in specimens of a 
very unusual size. 

At the sale of M. Dree's cabinet, a turquoise of 
the old rock, measuring "47 inch by "43 inch, was 
sold for $93 ; and as an example of the wide dif- 
ference between the turquoises of the old and the 
new rock, there was sold at the same sale, for 
$22-50, a turquoise of the new rock, -39 inch by 
•37 inch, of the most beautiful sky-blue tint. 

The turquoise is the stone that the orientals 
employ most frequently for amulets. Sentences 
are frequently engraved upon them, and generally 
quoted from the Koran. 

Occidental Turquoise. — The occidental turquoise 



ENGRAVING UPON THE TURQUOISE. 1 43 

is a substance altogether special in its composition, 
and above all in its organic origin. 

It is, in point of fact, a fossil ivory, produced 
from the teeth of a past race of animals, brought 
accidentally in contact with substances containing 
cop^r, and which has absorbed a sufficient quan- 
tity of them to colour the entire mass with a 
cerulean hue more or less deep. 

ENGRAVING UPON THE TURQUOISE. 

The low degree of hardness possessed by the 
turquoise probably deterred the ancients from often 
engraving on this stone, or, it may be, these speci- 
mens of antiquity have not been sufficiently durable 
to reach our time. In either case, there are very 
few engraved turquoises known. Caire, however, 
cites a few. 

In the Genevosio collection there is an amulet, 
convex on one side and flat on the other, showing 
upon one side an engraving of a veiled Diana hold- 
ing two branches in her hands, upon the other a 
sort of sistrum, a star, and a bee : Greek letters are 
inscribed upon both faces. 

The cabinet of the Duke of Orleans contained 
two engraved turquoises; one representing Diana, 
with her quiver upon her shoulder; and the other, 
the elder Faustina. 

A turquoise in the gallery of Florence, nearly as 



144 PRECIOUS STONES. 

large as a small billiard ball, is engraved with a 
head which is possibly that of Caesar, but more 
probably of Tiberius. 

The group which we have just examined compre- 
hends a certain number of precious stones that may 
be easily confounded with each other, or with cer- 
tain other gems of which we have yet to speak. 

As will be seen from the table at the end of the 
book, in which are briefly stated the general charac- 
ters of precious stones, it is almost always possible 
to distinguish with tolerable facility those that at 
first sight might be confounded. 

Thus, the transparent and colourless corundum 
resembles the diamond, the aquamarine, the colour- 
less spinel, and the quartz. 

Now the corundum has double refraction, and 
the diamond simple refraction; accordingly nothing 
else is necessary than to look at the flame of a 
candle through the doubtful stone, in the manner 
pointed out in Chapter i. 

The specific gravity of the corundum — 3*9 — 
enables us to distinguish it at once from quartz, of 
which the specific gravity is only 2*65, and from the 
emerald, which has a specific gravity of about 2 ■67. 
The white spinel, which, like the diamond, possesses 
simple refraction, will be distinguished from the 
corundum by the same optical test. 



METHODS OF DISTINCTION. I45 

The red-coloured corundum may be confounded 
with the red spinel, the red tourmaline, and the 
burnt topaz. 

The optical distinction applicable to the colour- 
less spinel is equally so to the coloured spinel. 
The tourmaline and burnt topaz, again, may be 
easily distinguished from the corundum by their 
specific gravities alone — that of the tourmaline 
being 3-07, that of the topaz 2-65. 

The oriental sapphire may be mistaken for the 
water sapphire or the blue emerald; the green 
corundum for the emerald of Bogota; the yellow 
corundum for the yellow topaz, the yellow quartz, 
the cymophane, and the zircon. The occidental 
amethyst, lastly, may be confounded with the 
oriental amethyst. 

In all these cases the specific gravities are often 
sufficient, and when employed in conjunction with 
the other characters indicated in the general table 
they always enable us to decide with certainty. 



10 



PART V. 



Quartz. Occidental Topaz. Smoky Topaz, or Alengon Diamond. 
Water Sapphire. False Emerald. Bohemian or Brazilian Ruby. 
Hyacinthe of Compostella. Iris. Aveniurtne. Opal. Hydrophane. 
Agate. Chalcedoizy. Chrysoprase. Cacholong. Heliotrope. Onyx. 
Sard. Sardonyx, Sardoine. Sardagate. Jasper. 

Zircon. Garnets. Peridot. Olivine. Jade. Tourmaline. Lapis- 
lazuli. Malachite. Hematite. 



" Some seek amidst the pebbles of the stream 
The verdant beryl, or the diamond's gleam. 
Or where the bright green jasper meets their view. 
Or the clear topaz shows its lighter hue. 
Or the sweet amethyst which, serenely bright. 
Diffuses far and wide its tranquil light." 



The stones of which we are now about to speak fall 
naturally into two classes, the first composed almost 
exclusively of silica, the second having a com- 
position more complex. The latter class contain a 
considerable proportion of silica also, but it is 
always combined with one or more substances, the 
nature of which varies in every stone. 

FIRST CLASS. 
The stones comprised in this class may be 



QUARTZ. 147 

arranged, from an artistic point of view, into three 
very distinct sections. 

The first includes all the stones formed of pure 
silica crystallized. 

The second comprehends all the stones formed of 
pure silica not crystallized. 

The third includes the stones formed of silica, 
always nearly pure, but containing some traces of 
colouring substances, which, however insignificant 
their quantity, communicate, in a commercial and 
artistic sense, a value to the stones that is alto- 
gether special. 

In the first group are placed quartz or rock cry- 
stal, and all its varieties. The latter bear very 
different names in commerce, but their composition 
is almost identically the same. If a piece of white 
silk were cut into shreds, and each of these pieces 
plunged into a dye of different tint and intensity, 
a different name might easily be given to each 
fragment according to its colour; but its substance 
would still be the same. Quartz holds the same 
relation to the precious stones of the section we 
are about to consider, as the white silk would bear 
to the tinted morsels we have described. 

FIRST SECTION. 
QUARTZ. 

Quartz, which is called also rock crystal, is one of 



148 



PRECIOUS STONES. 



the substances most frequently occurring upon the 
surface of the earth, and probably also in its interior. 
"It forms," says an English writer, "about one- 
third of the mass of those immovable hills whose 
summits pierce the clouds, and nearly the whole of 
the mobile soil of the trackless desert rolling with 
the wind like the waves of the sea." 





Fig. 67. — Primitive form of Quartz. 



Fig. 68. — Most ordinary form of 
Quartz Crystals. 



Crystals of quartz do not often occur of dimen- 
sions sufficiently great to attract the eyes of the 
common observer. Some magnificent specimens, 
however, are found in the ancient formations, which, 
as we have mentioned, are formed principally of 
silica: here indeed we would naturally look for 
them ; but that which would seem much less pro- 
bable, and yet actually occurs, is the presence of 



QUARTZ. 



149 



magnificent crystals of quartz, of an absolute purity, 
in the midst of rocks nearly exempt from all trace 
of silica; in Carrara marble, for example, and in 
certain gypseous formations in the south of France. 
Quartz is formed by the union of two bodies; 
the one, silicon, is a substance analogous to carbon ; 



^■g 




Figs. 69 and 70. — Modified Crystals of Quartz. 

the other, oxygen, is a gas, and one of the principal 
constituents of atmospheric air. 

The primitive form of quartz is the rhombohedron, 
but the primitive crystals are extremely rare. The 
most common form is the regular hexagonal prism 
terminated with six-sided pyramids (Fig. 68). 

It is rare for the terminal pyramids to have all 
the faces equal. Ordinarily, on the contrary, three 
of these faces are developed at the expense of the 



I5P 



PRECIOUS STONES. 



other three, and thus we have the crystal repre- 
sented by Fig. 69. 

In other cases the crystals are not terminated by 
pyramids, but by ridges, as in Fig. 70. In this 
case the form of the crystals is greatly altered, and 
the regularity, to a certain extent, disappears. 

If in the regular crystal (Fig. 68) we suppose the 
prismatic part to be diminished little by little with- 
out the form being otherwise changed, then, when 




Fig. 71. — ^Dodecahedral Quartz. 

the prismatic portion is quite removed, and the 
pyramids are applied base to base, the crystal re- 
presented by Fig. 71 is obtained. It is a dode- 
cahedron, all of whose faces are equal, and bounded 
by isosceles triangles. 

Crystals of this form occur in the midst of the 
gypsum which accompanies the ophites of the Pyre- 
nees. Numerous examples of perfect purity occur 
also in the gypsum beds of Provence, which belong 
to the trias formation. 



QUARTZ. 151 

Crystals do not ordinarily attain large dimen- 
sions. For the greater number of minerals, crystals 
of 2 inches are almost gigantic: few indeed ex- 
ceed 4 inches in height. Quartz, however, forms 
an exception to this rule. Specimens are brought 
from Madagascar more than 12 inches in length, 
and remarkably pure and transparent, notwith- 
standing their great size. The rock crystal of this 
island is used for the object-glasses of astronomical 
telescopes. Magnificent crystals have also been 
found in the Alps; one of these Alpine crystals, 
taken in Italy by the French, was borne in triumph 
to Paris in 1797. There is a beautiful specimen 
in the Museum of Natural History at Paris which 
measures 3 feet every way, and weighs nearly 800 
pounds. It was found at Fischbach in the Valais. 

At the French Exhibition of 1866, in the sections 
of Japan and of Brazil, there were some wonderful 
crystals. One crystal brought from Brazil weighs 
212 pounds, is 2^ feet high, and i foot in diameter, 
and is a perfect six-sided prism. 

A remarkable phenomenon in quartz is exhibited 
by the fluid drops which are contained in many 
specimens. Sir David Brewster ascertained that 
the fluid is not water, but of an oleaginous 
nature, one part volatile at twenty-seven degrees, 
and the other a fixed oil. Prof Dana has named 
the former cryptoline, and the latter brewsterine. 



152 PRECIOUS STONES. 

Some beautiful specimens of quartz crystals, beaded 
with these imprisoned drops, have been found at 
Trenton Falls, in the state of New York. 

EMPLOYMENT OF QUARTZ IN THE FINE ARTS. 

Quartz has but little value of its own ; but when 
it is made into vases, cups, and other artistic ob- 
jects, it acquires a high price. 

The Athenians produced some exquisite works 
of art in rock crystal, and the Romans valued it 
very highly in the form of vases. Nero had two 
cups of it, which he broke in his rage when he 
heard of the revolt that caused his downfall. One 
of these cups was estimated at over Si 900. 

The elegantes of Rome were in the habit of 
using balls of rock crystal to cool their hands, and 
certain occult charms were also said to reside in 
these cold smooth globes. 

In the middle ages the Venetians produced some 
beautiful objects in rock crystal; and Milan has 
long been famous for its statuettes, vases, and 
girandoles of this material. But desire of gain has 
deteriorated the artistic value of these productions ; 
cut crystals have come to be sold by weight, and 
the cutting is naturally falling into neglect. 

In the cathedral at Milan the burial shrine of St. 
Charles Borromeo is wholly formed of plates of 



COLOURED QUARTZ. 1 53 

rock crystal of 6 or 8 inches square each, set in 
a framework of silver. The shrine was the gift 
of Philip IV. of Spain, who employed eight years 
in collecting the necessary quantity of rock crystal. 

COLOURED QUARTZ. 

When crystals of quartz are found combined 
with certain traces of colouring matter, they con- 
stitute distinct species in commerce, and take com- 
pletely different names. 

Combined with iron and alumina quartz becomes 
yellow, and takes the name of the occidental or 
Bohemian topaz. 

Impregnated with a bituminous substance it be- 
comes more or less darkened, and is called the 
smoky topaz, or Alenqon diamond. 

Combined with a slight proportion of oxide of 
manganese it takes a beautiful violet colour; it is 
then the occidental amethyst. 

Coloured blue by iron and alumina, it becomes 
the water sapphire. 

Coloured rose by iron and manganese, it is the 
Bohemian or Brazilian ruby. 

Combined with a notable proportion of oxide of 
iron, it becomes a brown red, and constitutes the 
hyacinth of Compostella. 

But among all these varieties there are only two 



154 PRECIOUS STONES. 

that are really valuable — the amethyst and the 
water sapphire. 

OCCIDENTAL AMETHYST. 

The amethyst, whose violet colour varies accord- 
ing to the quantity of oxide of manganese com- 
bined with the silica, has all the properties of 
quartz. 

This substance is found in France, Prussia, Hun- 
gary, Arabia, Ceylon, Kamtschatka, &c. The en- 
virons of Carthagena in Spain furnish the most 
beautiful specimens of amethyst ; and they are the 
more remarkable that they show a purple reflection 
vying with that of the oriental amethyst. 

Brazil furnishes to commerce at the present day 
the greater number of amethysts. In that part of 
the world amethysts attain an enormous size. A 
block of amethyst, sent from the Brazils to Calcutta, 
is said to have weighed 98 pounds. Some of the 
Brazilian specimens are of two colours. The Count 
de Bournon possessed a cut and polished stone of 
this kind half violet and half yellow. 

The ancients believed that wine, when drunk 
from an amethyst cup, lost the power of causing 
intoxication. Accordingly the attributes of Bacchus 
and Silenus are frequently found engraved upon 
ancient cups of amethyst. 



WATER SAPPHIRE. 155 



WATER SAPPHIRE. 



The water sapphire has nothing in common but 
the colour with the oriental sapphire ; and even its 
colour — a clear white mixed with sky-blue — ex- 
hibits to the most inexperienced eyes a shade 
completely different from the magnificent velvety 
blue of the oriental sapphire. 

There are water sapphires composed of nearly 
pure quartz; but those brought from Ceylon are of 
a much more complex composition. Somewhat 
more than half their weight is silica ; the rest is a 
combination of alumina, magnesia, oxide of iron, 
and oxide of manganese. This variety is called 
dichroite, on account of its curious property of 
showing two very dissimilar colours when viewed 
from different sides — a beautiful blue in the direction 
of the axis, and a yellow gray in a direction perpen- 
dicular to this line. 

IRIS. 

Although this stone is no longer mounted by 
jewellers, and is only seen in antique jewels, it 
must not be passed over in silence; both because it 
was held at one time in high repute, and because it 
is liable to be confounded with several precious 
stones, particularly the opal. 

The iris is a very limpid and very transparent 



156 PRECIOUS STONES. 

quartz. It is crystallized, a fact which immediately 
distinguishes it from the opal. 

Under the influence of the light the iris is 
illumined with all the tints of the rainbow. This 
effect is produced by a great number of flaws and 
natural crevices contained in its interior; but its 
fires are always much less close than those of the 
opal. 

Notwithstanding the neglect into which it has 
fallen, the iris was once very highly thought of 
Much was said in the time of the First Empire of a 
certain parure of iris sometimes worn by the Em- 
press Josephine. It is described among regal 
jewels in the Lapidarium of Marbodus: 

" By the Red Sea the swarthy Arabs glean 
The iris, splendent with the crystal's sheen ; 
Its form six-sided, full of heaven's own light. 
Has justly gained the name of rainbow bright." 

THE AVENTURINE. 

The aventurine is a quartz of a clear brown or 
reddish-white colour, sprinkled with little spangles 
of yellow mica, that glitter like gold. It has been 
found also with a ground colour of yellow, of light 
gray, and of greenish-white. 

The yellow variety has been called sunstone. It 
is very scarce, and exceedingly beautiful. 

All aventurines do not owe their reflections and 
glitter to particles of mica. There is a kind — and 



THE AVENTURINE. 157 

that too pre-eminently esteemed — in which effects 
of this kind are produced by the presence of little 
crystals of quartz scattered through the mass, and 
reflecting the light on all sides. This last variety 
has generally a very clear tint of greenish-white, or 
sometimes of a reddish-brown. 

The aventurine with mica was formerly brought 
from the borders of the White Sea ; but at present 
it is furnished by Silesia, Bohemia, Siberia, and 
France. The species with crystals comes from 
Spain, and has for some years been produced by 
Scotland also. 

Many substances are sold in commerce under the 
name of aventurine that produce similar effects, but 
are quite different in composition, particularly cer- 
tain varieties of felspar, filled with flaws and minute 
fissures. 

SECOND SECTION. 

Before commencing the study of the stones com- 
prised in this section, it is necessary to make an 
important remark. 

So far the stones that we have examined are 
crystallized, and nearly always anhydrous. It is 
quite otherwise with those that are to be described 
in this group. They show no indication of crys- 
tallization, and nearly always contain water. 

It is probable that their elements have never 



158 



PRECIOUS STONES. 



been either melted by the direct action of heat, or 
deposited by the evaporation of a dissolving liquid. 
Everything, on the contrary, leads to the belief 
that they existed primitively in a gelatinous mass 
suspended in water. 

Certain results produced by one of the grand 




Fig. 72. — The Great Geyser (Opals and Chalcedonies). 



natural phenomena of our own time sustain this 
opinion. 

The boiling waters of the Iceland geysers — that 
at irregular intervals are projected upwards some- 
times to the height of fifty yards into the air — are 
heavily charged with silica ; and this substance, de- 



THE OPAL. 159 

posited little by little, produces at last enormous 
piles. 

In these silicious masses are found branches of the 
birch-tree completely silicified, and in the midst of 
a reddish clay a thin layer of chalcedony, which, so 
long as it remains watery, is translucid, but when 
dry becomes opaque and like white enamel. 

In these same deposits of the geysers small 
portions of silica are found, which perfectly resemble 
the noble opal so long as they remain hydrated; 
but they lose their vivid colours when they are 
dried. 

M. Descloizeaux is disposed to conclude from 
this observation that opals and chalcedonies found 
in volcanic earths had their origin in phenomena 
analogous to those of the Iceland geysers. 

THE OPAL. 

The opal is formed of silica like the stones of 
the first group ; but it differs from them by the con- 
stant presence in its composition of a certain quan- 
tity of water, making 5 to 12 parts in 100 of its 
weight. M. Damour has shown, moreover, that 
when sulphuric acid is applied to the opal the stone 
turns black, leading to the conclusion that it con- 
tains organic matter, probably bituminous. This 
the sulphuric acid would seem to destroy by setting 
its carbon at liberty. 



l60 PRECIOUS STONES. 

The opal has no colour that may be called its 
own, but a faint bluish tinge analogous to the tint 
of certain resinous quartz, of which it is a variety. 

Its true beauty and its great value are produced 
by a physical accident ; it is traversed by a multi- 
tude of- fissures filled with air and moisture, which 
reflect all the prismatic colours. The tender violet 
of the amethyst, the blue of the sapphire, the green 
of the emerald, the golden yellow of the topaz, and 
the flashing red of the ruby, appear at times isolated 
in certain parts of the stone, at times crossing each 
other in vivid play with an effect that is magical. 

The opal is found in Arabia, Ceylon, Hungary, 
Saxony, Ireland, Iceland, Scotland, and Mexico. 

Hungary and Mexico furnish the greater number 
to commerce; and some beautiful specimens have 
been recently brought from Honduras. The stones 
from all these places are true opals. Connoisseurs 
can usually distinguish the precise locality from 
which they are derived at a glance. 

The opal occurs in veins or gangues in ancient 
formations, and is not scarce; but the parts that, 
after cutting, will display all the storied fire of the 
opal are very rare. 

Beginning at the resinite quartz without fissures, 
and consequently without fire, and choosing suc- 
cessively fragments more and more closely fissured 
until the maximum is reached of the effect of light, 



THE OPAL. 



i6i 



an endless series of opals is obtained ; but in com- 
merce only three varieties are recognized — 

The Oriental Opal. 
The Fire Opal. 
The Common Opal. 

The oriental opal, called also the noble opal and 
the harlequin opal, shows generally in its fire a tri- 
angular disposition very characteristic. It exhibits 
flashes or flames of the most brilliant colours. 

The affection that the ancients entertained for 
this beautiful gem was unbounded. The Roman 
senator Nonnius preferred exile to parting with a 
brilliant opal the size of a filbert, which Mark 
Antony coveted. 

A very beautiful opal, considered by the virtuosi 
of Vienna and Dresden as the third in rank of the 
beautiful opals of the world, is described by Jack- 




Fig. 73. — Opal of D'Augny. 



son as having three longitudinal bands of the harle- 
quin kind, from the uppermost of which rose perpen- 
dicularly the most resplendent flames. It measured 

II 



1 62 PRECIOUS STONES. 

nine lines by six. In the last century the two most 
famous opals belonged, one, round and very brilliant, 
to the amateur Fleury; the other, fascinatingly 
vivid — an oval of the dimensions of Fig. y^^ — to the 
distinguished financier D'Augny. 

The fire opal is furnished principally by Mexico. 
Its colour, more pronounced than that of the orien- 
tal opal, and the carmine or vinous red tint of its 
fires, permits it to be easily recognized. At its 
maximum of effect the fire opal is brilliantly lovely; 
but its beauty is easily deteriorated by atmospheric 
influence. 

The comjnon opal displays very little fire,; its 
colour is milk-white, which, joined to a texture ex- 
tremely homogeneous, renders it semi-transparent. 

It is said that since the opal was introduced by 
Sir Walter Scott into his novel oi Anne of Geier stein, 
its favour has sensibly declined ; and the gem, con- 
sidered by the ancients to exercise the combined 
virtues of the amethyst, ruby, and emerald, is 
branded now as " an unlucky stone." 

ENGRAVING UPON THE OPAL. 

The work of engraving upon the opal is very 
difficult, and often quite impossible, on account of 
the thousand fissures of the stone. Besides, the 
fine effects of light which give it special value are 



THE HYDROPHANE. 1 63 

only attainable in the maximum degree by simple 
polish. 

An antique engraving upon a presumable opal 
is a head of Sappho; and in the collection of the 
Duke of Orleans was a head of Juba engraved upon 
an opal. There is, too, in the national collection 
at Paris, an opal engraved with a portrait of 
Louis XII. 

THE HYDROPHANE. 

The hydrophane, composed of 93 in 100 parts of 
silica, 2 of alumina, and 5 of water, is a very cele- 
brated stone, known from early antiquity. 

In its ordinary state the hydrophane is a white 
or reddish-yellow substance, feebly translucent or 
completely opaque. But if it is plunged into water 
it disengages little bubbles of gas, and at the same 
time becomes transparent, and sometimes displays 
the colours of the opal. 

Taken from the water this curious stone keeps its 
transparency for a short time, but gradually as the 
water evaporates becomes once more opaque. 

The ancient mineralogists, considering this stone 
an unexampled marvel, gave it the name of Oculus 
Mundi, the " eye of the world." 



1 64 PRECIOUS STONES. 

THIRD SECTION. 
AGATE. 

The agate, unlike other precious stones, very 
rarely occurs in veins; it is almost always in the 
state of concretions; sometimes in the form of 
geodes or balls. Occasionally there is found in the 
side of one of these balls a sort of funnel through 
which the silicious matter was introduced. 

Sometimes the gelatinous silica has been abun- 
dant enough to give rise to homogeneous deposits 
of a certain depth ; the stone in that case is of uni- 
form colour; but often the deposits are in very thin 
layers, and of different shades of colour ; often, too, 
they are moulded by the cavities of the body which 
forms their support, and take from its irregularities 
all sorts of dispositions with very variable shadings. 

In cutting a section across a stone of this cate- 
gory, extremely different effects are obtained by 
following different directions. The varied zones 
and colours of the stone produce, too, infinite 
varieties; and descriptive names have been be- 
stowed upon agates, according to these changes, as 
rainbow, cloud, moss, star, ruin, landscape, fortifi- 
cation agate, &c. The differences between all these 
varieties are extremely slight in a physical or 
chemical point of view. 



AGATES. 165 

Agates are divided naturally into two varieties: — 

Agates of a single tint. 
Agates of several tints. 



FIRST VARIETY. 

Chalcedony. — The chalcedony is quite a common 
stone, of a dull or milky-white; and sometimes of a 
bluish tint, when it is called saphirine. 

The ancients obtained chalcedony from Egypt 
and Syria, and it was an object of considerable 
commerce at Carthage. It probably derived its 
modern designation from Karchedon, the Greek 
name for Carthage. It is found in England, Ire- 
land, Germany, Italy, &c. 

Chrysoprase. — Chalcedony coloured by the oxide 
of nickel, varying in colour from deep verdigris to 
the palest green. It takes a very beautiful polish, 
and fifty years ago was fashionable in jewelry, 
though now quite forgotten. 

Cacholong. — A variety of chalcedony of a whitish 
tint, cloudy almost to opacity. It is found in 
Bokhara, Ireland, Greenland, and the Faroe 
Islands. 

Cornelian. — A species of chalcedony, but of a 
finer grain. The ancients confounded it with the 
sardoine, and it was not until the thirteenth century, 
in the writings of Albertus Magnus, that the dis- 
tinction became established. 



l66 PRECIOUS STONES. 

The cornelian has sometimes the colour of 
polished horn ; there is one variety that resembles 
the hyacinth, and another, of vermilion red, some- 
what analogous to the ruby. Its colouring is due 
to the oxide of iron, and in certain varieties to 
organic matter, clearly discernible by analysis. 

Heliotrope. — A translucid agate of a lively leek- 
green colour, spotted with red. The ancients used 
it, as Pliny tells us, for looking at eclipses of the 
sun, as we use smoked or stained glass ; and it was 
said also to change the colours of the sun's rays 
into blood-red, when it was plunged into a vase of 
water. Hence the name heliotrope, from the Greek 
helios, the sun ; and trepo, to turn. 

SECOND VARIETY. 

Onyx. — The onyx is the most celebrated variety 
of all the variously tinted agates. 

Originally the name onyx was given to agates 
which had the appearance of a nail (Greek, onyx) 
where it joins the flesh; but it is now used for 
stones which exhibit marked contrasts of colour in 
bands, as black and white, or black and, whitish- 
gray. 

When an onyx unites in a desirable degree these 
conditions, it constitutes a stone of value, on 
account of the resources offered by it to the en- 
graver, through the contrast of colours. 



JASPER. 167 

Sard. — This word, very anciently used, is said by 
Braunius to be derived from the Hebrew sered, "a 
red colour." However this may be, it is to agates 
of this colour that the name is applied. 

Sardonyx. — A stone formed, as its name implies, 
of the sard and the onyx, using the latter term in 
its primitive signification. The sardonyx is a 
stone displaying alternate layers successively 
whitish and carnation red. 

Sardoine. — Considered by many mineralogists as 
identical with sardonyx. Engravers, however, re- 
cognize between these two stones a marked differ- 
ence: for them, the sardoine is an agate whose deep 
colour partakes both of yellow and red without 
either colour predominating. In colour, therefore, 
the sardoine differs completely from the sardonyx. 

Sard-agate. — A semi-transparent stone formed of 
an inferior layer of orange-red or pale yellowish- 
red, and a superior layer of whitish tint, disposed 
one upon another with perfect regularity. 

JASPER. 

The precious jasper is the jaspeh of Aaron's 
breastplate ; the iaspis of the Greeks. 

"The property which distinguishes jasper from 
other varieties of quartz is its complete opacity even 
in thin flakes. Jasper is often a silex that has 



1 68 PRECIOUS STONES. 

become opaque either by alteration that it has 
undergone, or by the addition of a certain quantity 
of oxide of iron, or of hydrate of the same oxide. 
There are red jaspers, brown jaspers, and green jas- 
pers. In certain circumstances, as in the Egyptian 
pebble, the jasper presents irregular zones, which 
display a structure roughly concentric" (Du- 
frenoy). 

It is one of the thousand varieties of rocks known 
under the name oi jaspers. These varieties, hard 
enough to cut glass, present wide bands of diverse 
colours, generally red and green, upon a brown 
ground. 

The silicious element predominates in the jas- 
pers, but with it is associated certain bases (alumina, 
oxide of iron, &c.), sufficient to render the whole 
fusible under the flame of the ordinary blowpipe, 
which is not the case with quartz or its varieties 
that are very nearly pure. 

The substances known in commerce under the 
name of jaspers differ so greatly from each other 
that their price varies from 20c. to $12 the pound. 

ENGRAVING UPON AGATE, &C. 

It is the agate, and the varieties of which it is the 
type, that have in all ages furnished to the engraver 
the stones best suited to his art. 



ENGRAVING UPON AGATE. 



169 



One of the most remarkable engravings upon 
agate, and one of the finest specimens of this stone, 
is represented by Fig. 74. It is the bust of Alex- 
ander the Great. The head is carved in relief, and 




Fig. 74. — Agate, Alexander the Great (reduced to three-quarters). 

its colour is quite different from that of the ground- 
work of the stone. It is set in a superb frame of 
enamelled gold. 



170 



PRECIOUS STONES. 



The fig. following (Fig. 75) is a chalcedony dis- 
playing a bacchic bull with an ivy wreath around 
his body and a thyrsus under his feet. It is one of 
the most celebrated of antique engraved gems, and 
bears the signature of the famous graver Hyllus. 

As a specimen of modern engraving, we represent 
by Fig. ^6 that celebrated stone known as the "seal 
of Michael Angelo." It is a small transparent cor- 
nelian engraved en creux or entaille. In the small 





Fig- 75. — Cameo of Hyllus. 



Fig. 76. — Seal of Michael Angelo. 



space of an oval, hardly more than half an inch in 
length, there are fourteen figures, besides the 
scenery of a river with water-monsters and a fisher- 
man. It is a bacchanalian or vintage scene, and it 
recalls a part of Michael Angelo's fresco of " Judith 
committing the head of Holophernes to her atten- 
dant." Critics are at variance concerning this cor- 
nelian : it has been ascribed to the famous engraver 
Pyrgototes,with the supposition that Michael Angelo 
used its design as a passage of his great fresco; 
and, on the other hand, it is called a modern chef- 



THE ZIRCON. 171 

d'oeuvre, whose engraver has been inspired by 
Michael Angelo. 

This stone was in the cabinet at Versailles, and 
was one day swallowed by an enthusiast in gems; 
but fortunately Hardion, who was exhibiting the 
tr^sures, observed the act, and before the honest 
man departed persuaded him to take an emetic for 
the benefit of his stomach. The gem was in this 
manner immediately recovered. 

SECOND CLASS. 
THE ZIRCON, 

The zircon, called also the jargon, is altogether 
special in its composition, being formed of silica, 
united with a peculiar mineral — zircona, the oxide 
of zirconium. 

The zircon crystallizes in four-sided prisms, with 
various modifications. Fig. ']'] shows the primitive 
form, and Fig. 78 a modification approaching the 
form of the dodecahedron. 

Generally speaking, each of the two types has its 
own particular colour, which is shared by the crys- 
tals belonging to it. The first is a brownish and 
greenish-yellow, the second brownish-red. Werner 
called the rhomboidal type hyacinth, and the pris- . 
matic zircon. Ancient lapidaries made the same 



1/2 PRECIOUS STONES. 

distinction, and the stone that Werner calls zircon 
is their j'arg-on of Ceylon. 

The colourless crystals of the zircon are the most 







/ 

7 


i 




Fig. 77.— The Zircon. Fig. 78. — Modified Zircon. 

valued. They take on an excellent polish, display 
an adamantine lustre and fire, and will pass for dia- 
monds if not too closely inspected. The zircon, 




Fig. 79. — Zircon from the Cabinet of M. Dree. 

accordingly, is sometimes introduced into orna- 
ments, and sold to inexperienced people as a dia- 
mond, a particularly gross fraud, inasmuch as the 
zircon has but a very trifling value. Indeed even an 



GARNETS. 173 

exceptional zircon, of a beautiful olive-green tint, of 
the dimensions shown in Fig. 79, was sold at the 
auction of M. Dree for the sum of $16. A dia- 
mond of the same dimensions, even if only a rose, 
would weigh about 5 carats, and would bring not 
less, than $1800. 

The finest specimens of zircon are brought from 
Ceylon ; but they are also found in Europe, in the 
vicinity of Lisbon, and in France, near the town of 
Puy. 

GARNETS. 

With materials which, though different in their 
nature, are cut and placed in the same manner, it 
is possible to construct several edifices resembling 
each other in form and disposition. 

That which Art accomplishes more or less com- 
pletely, Nature realizes perfectly. 

Out of substances essentially differing in their 
nature she constructs well-defined and crystallized 
compounds, which appear to all intents and pur- 
poses identical, and yet are not so. 

This phenomenon is called in science isomorphism, 
from the Greek isos, equal; and morphe, form. It 
was discovered by the celebrated German chemist 
Mitscherlich, and the discovery is considered one of 
the greatest scientific achievements of our century. 



1/4 PRECIOUS STONES. 

The group of minerals designated by the name 
of garnets furnishes one of the most remarkable 
applications of the grand theory of isomorphism. 

Under this name are comprehended minerals dif- 
fering much in colour, in specific gravity, in chemi- 
cal composition, &c. ; but whose fundamental form 
never changes, and which even presents a very 




Fig. 80. — Garnet, Rhomboidal type. Fig. 81. — Garnet, Trapezohedral type. 

small number of secondary modifications. Garnets 
are always crystallized, and they appertain to the 
tesseral system. Two secondary forms only are 
nearly always produced, the rhombic dodecahedron 
(Fig. 80), and the trapezohedron (Fig. 8i). 

In a scientific classification Rose, and the greater 
number of mineralogists with him, admit eight 
species of garnets, but two only furnish products for 
jewelry ; these are: — 



GARNETS. 175 

The Grossularia. 
The Almandine. 

Grossularia. — This species is a double silicate of 
lime and alumina. As its constituents are col- 
ourless, either alone or combined, we should meet 
with limpid garnets devoid of any tint. Such gar- 
nets, in fact, are found in certain localities of Nor- 
way, Mexico, and the Ural Mountains. But as 
iron — which Haiiy has called " the great colourist 
of nature " — is so extremely abundant, it becomes 
introduced in proportions more or less considerable 
into the grossularias, and the result is that the 
limpid garnets become tinted with green, clear red, 
orange red, &c., according to the quantity of iron 
combined. The varieties of Ala in Piedmont, so 
remarkable for the vivacity of their lustre and the 
purity of their forms, are grossularia. There are 
also certain yellow varieties in Siberia which re- 
semble in colour the spinel ruby. 

The analysis of a colourless garnet of the Ural 
has given the following results: — 

Silica, 3866 

Alumina, 24' 19 

Lime, 3715 

100 00 

Almandine. — This species is a double silicate of 
alumina and iron; it is the grossularia with its lime 
replaced by oxide of iron. Often, however, the 
lime is not completely replaced, and the iron is not 



176 PRECIOUS STONES. 

the only principle substituted, but then it is accom- 
panied by an equivalent proportion of magnesia or 
oxide of manganese. 

The beautiful variety of yellow garnet called 
pyvope belongs to the almandine species. It differs 
only from the type by a little quantity of the oxide 
of chromium taking the place of an equivalent quan- 
tity of the other bases. This substitution is re- 
garded as perfectly regular by the mineralogist, but 
it produces a very agreeable colour, and gives com- 
mercially an altogether peculiar value to the 
pyrope. 

It is to the almandine species also that the garnets 
so well known in commerce as Bohemian garnets be- 
long. They are furnished by Bohemia, Saxony, 
and other parts of Germany. 

The most desirable garnet is the oriental or 
Syrian garnet. Its composition varies, but its 
lustre and beauty place it above all others. Its 
name is not derived from Syria, as is often sup- 
posed, but from the Syrian, a river in the country 
called Pegu in Asia. It was from that country, 
indeed, that the first specimens were brought ; but 
this commercial species is found equally in the Isle 
of Ceylon and in Brazil. 



PERIDOTE, OLIVINE. 1/7 

EXCEPTIONAL GARNETS, AND ARTISTIC APPLI- 
CATIONS OF THIS STONE. 

At the sale of M. Drue's cabinet, a Syrian garnet 
of an octagonal form, j^ inch by t%-, was sold 
foi!»$65o. Another, fire-red, i inch by i% inch, 
attained the price of $i86. 

Among engraved garnets may be mentioned the 
head of the dog Sirius, a chef-d'oeuvre of Coli, 
a mask of Silenus crowned with vine-branches, a 
fine bust of Hadrian in the Odescalchi Museum, 
and a celebrated Venus Genetrix in the cabinet of 
the Abbe Pullini at Turin. 

PERIDOTE, OLIVINE. 

The peridote is a stone very anciently employed 
in jewelry; and as up till late years it was only 
found in water-worn fragments, its form of crystal- 
lization could not be determined. The recent dis- 
covery, however, of well-defined crystals of peridote 
on Vesuvius shows that they appertain to the right 
rhomboidal prism. 

The peridote is a double silicate of magnesia and 
iron, with variable proportions of manganese, 
alumina, and sometimes nickel. According to the 
nature and quantity of the metallic compounds that 
enter into its composition, the peridote exhibits 

12 



1/8 PRECIOUS STONES. 

crystals of different colours. The peridote, properly 
so called, is a yellow-green; other varieties have 
clear olive-green tints, and are called by the lapi- 
daries olivines. 

The crystals of peridote are sometimes called chry- 
solite, but this must not be confounded with oriental 
chrysolite or cymophane. 

An interesting fact attaches itself to the peridote. 
It is, among all the precious stones, the only one 
which has to this time had the honour of being 
found in those stones dropped from space, which we 
designate under the name of aerolites. 

The peridotes of commerce are brought from the 
Levant by way of Constantinople, but the exact 
locality in which they are found is not known. 

JADE. 

This word is a generic term used to designate a 
certain number of substances, which, while re- 
sembling each other in many characteristics, differ 
materially in their composition. 

These common characteristics are great hardness: 
wonderful tenacity, a wavy or scaly fracture, a cer- 
tain oily lustre, and tints of white, greenish-white, 
milk-white, and rose-white. 

The best known variety is brought from China; 
it is a silicate of lime and magnesia, with traces of 



JADE. 179 

oxide of iron, and sometimes of oxide of man- 
ganese. 

Another variety, greatly prized by the ancients 
for its miraculous power of curing colics and the 
bites of venomous insects, is called nephritic jade, 
or, nephrite stone ; it is of a pale-green colour, 
sometimes with a slight tinge of lilac. 

Antique objects made of jade are so hard that 
they can only be cut by the diamond ; and as these 
objects are many of them of considerable dimen- 
sions, and their number is too great to suggest such 
difficult labour, it is supposed that when this jade 
was taken from the mine it was easily cut, and 
afterwards attained its hardness by exposure to the 
air, or perhaps by the direct action of fire. 

The jade of Saussure, found in Switzerland, is a 
species differing somewhat from the Indian jade; 
and the axe-stone jade is a product of South 
America. It has been called the amazon stone, and 
Humboldt says that the Caribbees used the jade 
stone as amulets, cut in the shape of the Perse- 
politan cylinders, longitudinally perforated, and 
covered with inscriptions. 

The principal mines of European jade are in 
Turkey and in Poland, where it is wrought into 
knife-handles, daggers, &c., and is softer than the 
oriental jade. 

The Chinese are particularly fond of jade, and 



l8o PRECIOUS STONES. 

work it into objects of great beauty. A sceptre of 
white jade was sent as a present from the Emperor 
of China to Prince Albert of England. 

TOURMALINE. 

The tourmaline holds but a secondary rank 
among those gems that are used for ornament, 
but, from a scientific point of view, it is well worth 
attention. 

The modern tourmaline is the lyncurium of the 
ancients. It is also called schojd, especially in 
Germany, from the name of a village in Saxony, 
where it is very abundant. 

Its composition is very complex ; there are, how- 
ever, certain elements which are characteristic of it, 
namely, boracic acid, silica, and alumina. In all 
tourmalines, also, there is an alkaline base, some- 
times potash, sometimes soda, sometimes lithia, or 
a mixture of all. There is found in it also mag- 
nesia, lime, oxide of iron, and oxide of manganese. 

The tourmaline is always crystallized, and its 
crystals appertain to the rhombohedral system. 
The crystals are in the form of longish prisms, 
sometimes with six faces, sometimes with nine, 
and in this case, in consequence of the obliteration 
or partial obliteration of faces, they terminate in 
such forms as shown in Fig. 82. 



LABRADORITE. l8l 

The tourmaline assumes a great many colours, 
and accordingly receives a great number of names. 
The Isle of Elba produces specimens from white 
to black ; a species from Siberia is a beautiful red ; 
from the Brazils both green and blue tourmalines 
are brought; and from Sweden a fine indigo-blue 
calle'ci indicolite. ' Berlin-blue tourmaline is called 




Fig. 82. — Tourmaline. 

Brazilian sapphire ; and there are green shades, 
which are called Ceylon or Brazilian emeralds. 

These blue and green tourmalines show in the 
most pronounced manner the phenomenon of di- 
chroism. 

LABRADORITE. 
The beautiful stone of Labrador, unknown until. 



1 82 PRECIOUS STONES. 

about a hundred years ago, it was discovered in the 
Island of St. Paul, near the coast of Labrador, is 
the type of one of the four great species formed by 
Rose, at the expense of the ancient group of the 
felspars. Its specific gravity is 2*6 to 27. 

The labradorite is called sometimes the opaline 
felspar, because it resembles the opal in its beauti- 
ful reflections of colours. The finest colours are 
a play of blue and green upon gray. Yellow and 
bronze-red are less common ; and a pearly-gray and 
purple-red still more rare. 

The labradorite is essentially formed of silica, 
alumina, lime, and soda. 

It has been found in its crystallized state 
scattered through volcanic productions, and notably 
in the lavas of Etna. 

LAPIS-LAZULI. 

The lapis-lazuli is a mineral whose beautiful blue 
colour varies from the palest tint to a deep blue, 
nearly black. The finest is a uniform colour of 
deep azure inclining to purple. Its specific gravity 
is 2 '6. 

Chemists differ in its analysis ; but it is known to 
contain silica and alumina, with a supplement of 
soda, lime, and sulphur. Its colour is of such en- 
during quality that the preparation made from it. 



LAPIS-LAZULI. 183 

called ultramarine, is never deteriorated by the 
air, and is consequently of the utmost value to ar- 
tists. Lapis-lazuli takes a beautiful polish, and is 
converted into many exquisite articles of ornament. 
It is found in Persia, Siberia, and Chili, but the 
m^t esteemed specimens are brought from China. 



APPLICATION TO THE FINE ARTS OF LAPIS- 
LAZULI. 

Lapis-lazuli is frequently engraved, and it is 
carved also into cups and vases. 

The French crown jewels contained some beauti- 
ful objects in lapis-lazuli; among them a cup in 
the form of a boat, of large dimensions, and valued 
at $37,200, and a sabre with a handle of lapis-lazuli 
given to Louis XVL by Tippoo-Saib, valued at 
$1116. 

Many beautiful specimens were exhibited at the 
Paris Exhibition; exquisite carving by Rudolphi, a 
marine shell carved of azure lapis-lazuli, finely 
mounted by Morrel, and chef-d'ceuvres by Dupon- 
chel and Jarny. 

In the Orlof palace at St. Petersburg some of the 
apartments are lined with this beautiful stone. 



184 PRECIOUS STONES. 

MALACHITE. 

Malachite, or "vert de montagne," is a hydrated 
carbonate of copper, or rather " a stalagmitic form 
of the green carbonate of copper " found in Siberia, 
Norway, and the Ural Mountains, and lately in 
South America. It is rarely found in masses 
weighing more than from ten to twenty pounds, 
and good specimens have a very high value. Its 
specific weight is 4. 

Malachite takes a fine polish, and its varied 
shades of green, disposed with a thousand caprices, 
or in diverse zones, give it a pleasing effect. Beads 
and pendants of it are occasionally seen in jewelry, 
but its chief use in art is for ornaments of larger 
dimensions, such as boxes, paper-weights, statu- 
ettes, &c. 

At St. Petersburg an exceptionally large slab of 
malachite 34 inches by 18 broad and 2 thick, is 
valued at S5294. 

Under the First Empire an apartment in the 
Grand Trianon was furnished with beautiful objects 
all made of malachite, and presented to Napoleon 
I. by Alexander of Russia. 

Attempts have been made to engrave malachite, 
but owing to its soft texture and multiplicity of 
zones destroying artistic effect, without successful 
results. 



HEMATITE. 1 85 

HEMATITE. 

The hematite is a sesqui-oxide of iron occurring 
with a fibrous or radiated structure in mammillated 
or globular masses, and greatly resembles malachite 
in Ae mode of its formation. 

It is a very common stone, of a dark-red colour, 
verging upon black. Properly speaking it is not a 
precious stone, but it is mentioned here because it 
is the first stone that ever was engraved. It is the 
material of the cylinders and the vases engraved by 
the Chaldeans, the Assyrians, the Medes and Per- 
sians, and Phenicians, in the remote time to which 
we refer the origin of art. 



PART VI. 

PearL Coral. Amber, Jet, 



' The sea-born shell conceals the unio round — 
Called by this name as always single found. 
One in one shell, for ne'er a larger race 
Within their pearly walls the valves embrace. 
At certain seasons do the oysters lie 
With valves wide gaping towards the teeming sky, 
And seize the falling dews, and pregnant breed 
The shining globules of th' ethereal seed." 



The pearl is an animal product secreted by cer- 
tain shell moUusca, of which one kind live in the 
sea, and the others in fresh water. Pearls are quite 
common, but those which have considerable dimen- 
sions, joined to a regular form and beautiful reflec- 
tions, are rare and of high price. 

Formed almost exclusively of lime and of an 
organic matter, the pearl is very easily acted on; as 
regards resistance, it has nothing in common with 
precious stones, even those most easily destroyed. 

The pearl was dedicated to Venus. It is sacred to 
love and beauty. In the " marriage of Cupid and 
Psyche " — a fine engraving upon sardonyx, wherein 
the figures are enveloped in transparent veils, a 



THE PEARL. 



187 



work of great difficulty in engraving upon stone — 
the lovers are united by a string of pearls — emblem 
of conjugal bonds — by aid of which the god Hymen, 
bearing a torch, conducts them to the nuptial couch 
(Fig. 83). 




■m^ 



Fig. 83.— Marriage of Cupid and Psyche, engraved upon a Sardonyx. 

A number of opinions have been expressed upon 
the origin of the pearl. The ancients poetically 
ascribed it to a drop of dew falling at morning or 
evening into the opened shell. 

" Brighter the offspring of the morning dew. 
The evening yields a duskier birth to view." 

It was once a common belief that the pearl was 
a morbid production of the animal. Above all, it 
has been thought that it originated in some foreign 



1 88 PRECIOUS STONES. 

substance, such as a grain of sand, or an animal 
parasite, introduced accidentally into the shell. 
This substance, it was supposed, tortured the ani- 
mal, which, to free itself from the irritation, covered 
it with a pearly secretion. Acting on these ideas, 
the Chinese are said to have obtained pearls artifi- 
cially, by piercing the shell, and slightly wounding 
the animal. 

There is probably some truth in these hypotheses; 
but an examination of the pearl under the micro- 
scope proves that such modes of formation are not 
the only ones employed ; and even that they do not 
necessarily enter into the formation of these beauti- 
ful productions. Indeed certain pearls show in their 
interior spherical cavities perfectly empty ; and 
others, which are completely solid to the centre, 
display in all their parts a regular and continuous 
texture, without the least trace of any foreign 
matter. 

A pearl of the first quality should possess, above 
all things, a fine orient, or water. By this expression 
is meant a pure whiteness, joined to a lively lustre 
that sparkles in the light. There are pearls, too, 
which, with a white colour, show a delicate reflection 
of azure. These are the most highly esteemed. 

The second quality of a fine pearl is, that it 
should be perfectly spherical, or regularly pear- 
shaped. 



THE PEARL. 1 89 

There are a great number of pearls whose colour 
has a yellowish tinge. This alone is a mark of 
inferior quality. 

It is very probable that pearls possessing this 
yellowish shade exist normally in the shell. Taver- 
nier, however, thinks that all pearls are white, and 
that' the yellow tint is induced by putrefied pro- 
ducts, resulting from the treatment of the shells in 
their places of production ; the pearl-shells being 
left in the open air that they may open of them- 
selves after the death of the animal. The work is 
thus accomplished without any expense, and with- 
out risk of breaking the pearls, an accident that 
occurs very frequently if the shells are opened arti- 
ficially. In support of his theory Tavernier states 
a fact, which, if established, would be conclusive; 
which is, that yellow pearls are never found in shells 
that have preserved their water. 

The shells in which pearls are found belong to 
several families of the large class of moUusca ; but 
the most important of all is the — 

Avicula margaritifera, Bruguiere; Pentadina 
margaritifera, Lamarck. This species not only 
produces the pearl, but furnishes to commerce vast 
quantities of mother-of-pearl of the kind most 
valued. 

There is a prevailing idea that mother-of-pearl 
and the pearl are of the same nature; and, in con- 



190 



PRECIOUS STONES. 



sequence of this notion, numberless attempts have 
been made to obtain artificial pearls by means of 
little spheres more or less regularly cut out of 
mother-of-pearl. 

The experiment has never been successful. A 
little serious examination of the subject proves that 
there is nothing to hope from this method. Even 
admitting that mother-of-pearl and pearl are the 
same in composition, which has not been scienti- 
fically proved, it is certain that they are not of the 
same constitution. Mother-of-pearl is much harder, 
and offers infinitely more resistance to the tools of 
the lapidary than the pearl. But that which is 
most important to be remarked is, that in the pearl 
the constituent layers are concentric, while in the 
pearls cut out of mother-of-pearl, the layers are 
more or less parallel. 




Fig. 84. — Pearl. Fig. 85. — Mother-of-pearl. 



Figs. 84 and 85 establish perfectly to the eye the 
complete difference presented in this respect by 
mother-of-pearl and the pearl. 



THE PEARL. TQI 

They show, at the same time, how the light must 
necessarily undergo very different modifications in 
the two cases, and why cut mother-of-pearl can 
never have the same optical effects as the pearl. 

Although pearl molluscs exist in all parts of the 
world, there are but few places where their gather- 
ing has become an industry. One of these places 
was formerly the Red Sea, which, in the time of the 
Ptolemies, produced an abundance of pearls. But 
the beds are probably exhausted ; at any rate they 
are no longer worked. The two regions which for 
a long time have produced the most beautiful pearls 
are the Persian Gulf, and the Straits of Manaar 
which separate Ceylon from the peninsula of 
India. 

More recently great quantities of pearl-oysters 
have been discovered in America, particularly in 
the Gulf of Mexico, upon the coasts of California, 
and in the vicinity of Panama. 

There have been experiments made to determine 
the time necessary to the development of a pearl. 
No very certain results have been obtained ; but it 
has been proved that at least two or three years 
are necessary for the formation of a pearl of any 
value. 

Hitherto the pearl shells have been gathered by 
divers, who, practising the pursuit from their 
earliest yeiars, end by being able to stay nearly six 



192 PRECIOUS STONES. 

minutes without breathing at the bottom of the 
sea. The prodigious efforts which they are obliged 
to make, and the considerable pressure to which 
they are subjected, result in a number of very 
grave accidents. The bodies, too, of the unhappy 
beings who devote themselves to this frightful trade, 
are very quickly covered with sores ; and very sel- 
dom does a pearl-diver arrive at old age. 

The remarkable appliances which render it possi- 
ble to stay under the water for a long time without 
much inconvenience have been introduced into the 
localities where there are pearl fisheries, and will no 
doubt diminish wonderfully the sad consequences 
so long inseparable from this deadly trade. 

Of all the objects employed as personal orna- 
ments, the pearl is almost the only one that derives 
nothing from art. On the contrary, all attempts 
made to give it more value only end in deterio- 
rating it. 

Pearls were among the first substances ever em- 
ployed as ornaments. As far back, indeed, as we 
can look into antiquity, we find them figuring in 
the first rank. 

The Indian mythology speaks often of the pearl, 
and attributes its discovery to Vishnu, who searched 
the ocean for these ornaments to deck his daughter 
Pandaia. The Book of Job and the Proverbs of 
Solomon also mention them. The accounts of 



THE PEARL. 1 93 

ancient historians show the estimation in which 
pearls were held by the Babylonians, the Persians, 
and the Egyptians. 

Everyone knows the famous story of Cleopatra, 
who, striving to rival the prodigality of Antony, 
dissolved in vinegar the pearl of one of her ear- 
rings, which had cost $706,800, and swallowed it. 
The possibility of this fact has been contested, but 
the thing is quite possible, only nothing more 
nauseous than the mixture can be imagined. 

This experiment may possibly have been tried 
upon real pearls without success, but then probably 
the action of the acid did not last long enough. 
The pearl, as we have seen, is formed of carbonate of 
lime, and an organic substance. The vinegar easily 
effects a soluble combination with the carbonate of 
lime; but as soon as the lime of the first layer is 
consumed, the organic matter of a gelatinous con- 
sistence continues to envelop the pearl ; and as this 
matter is not soluble in vinegar, nor can be attacked 
by it, a protection is formed around the interior 
layers, so that they are not reached by the corrosive 
liquid. But by persistence, in the end even this is 
penetrated, and the pearl is completely dissolved. 

The passion of the Romans for pearls, like all the 
passions of this people, was carriea to an extrava- 
gant height. 

The pearl which Caesar presented to Servilia, 

13 



194 PRECIOUS STONES. 

sister of the celebrated Gato of Utica, had cost 
$223,200. The Empress Lollia PauHna, wife of 
Caligula, wore, in a set of ornaments composed of 
emeralds and pearls, the value of $1,488,000. Cali- 
gula himself, Nero, and other of those cruel men 
whom history is obliged to name among her Roman 
emperors, ornamented their buskins and strewed the 
furniture of their saloons with pearls. Under the 
influence of the ideas of which we have spoken 
in Part ii. pearls acquired great importance in 
medicine. Even in our own time they are fre- 
quently employed medicinally ; and in China are 
chiefly valued on this account. Every year a large 
quantity are absorbed — generally in a dissolved 
state — by the inhabitants of the Celestial Empire. 

By the effects of time, and of external agencies, 
pearls lose the beautiful reflections which constitute 
all their value; often, too, under these influences, 
they become more or less yellowish. There are 
also natural pearls, of a beautiful form and ample 
size, which do not exhibit these reflections, and 
whose colour is generally rather deep. In both 
cases they are called dead pearls. In this state 
they are of very little value, and a thousand means 
have been tried to give them lustre. 

In certain cases the operation succeeds ; in others 
it is a complete failure. 

With great difficulty the present writer obtained 



THE PEARL. I95 

a certain number of secret receipts for restoring dead 
pearls to their primitive lustre. In one of these 
concoctions there are eighty-three ingredients, each 
one more whimsical than the last. In another the 
chief ingredient is dew gathered under certain con- 
ditions, and from the leaves of certain plants. One 
easily traces the influence here of the idea that the 
ancients entertained of the origin of the pearl. 

At first glance these receipts seem only to asso- 
ciate the most dissimilar elements, and those that 
could not possibly have any efficacy ; but the 
chemist discovers in them one remarkable fact: 
after the complex reactions of one substance upon 
another, there remains always the definite result of 
an acid liquor. 

Recalling now the constitution of the pearl, 
formed of concentric layers, and the facility with 
which it is dissolved by an acid liquid, one can 
easily see that a pearl plunged into this liquor will 
be attacked, and that its exterior layer will quickly 
disappear. If the pearl submitted to this operation 
is only yellow and opaque exteriorly, the removal 
of the layer thus modified will leave bare the nor- 
mal layers, and the pearl will recover its lustre. If, 
on the contrary, the layers are discoloured and 
opaque to the centre, nothing can restore it. In the 
first case the operation is a success; in the second 
it is a failure. The reason is no longer a mystery. 



196 PRECIOUS STONES. 

CELEBRATED PEARLS. 

The most celebrated pearl which has been seen 
in modern times is described by the famous 
traveller Tavernier. 

Found by an Arab in the neighbourhood of 
Catifa, it was purchased in 1633, hy the King of 
Persia, for the sum of $260,400. 

The pearl known as the Peregrma, bought by 
Philip II., king of Spain, weighed 134 carats; it 
was in the form of a pear, and of the size of a 
pigeon's &^^. It came from Panama, and was esti- 
mated at more than 50,000 ducats. 

Another still more famous pearl was brought 
from the Indies by Gorgibus of Calais, and pre- 
sented to Philip IV., king of Spain; it had the 
form of a pear, and weighed 1 26 carats. 

"How have you ventured," asked Philip IV. of 
the merchant, "to put all your fortune into such 
a little object.''" "I knew that there was in the 
world the King of Spain to buy it of me," the 
merchant answered. There was but one royal 
way of rewarding such faith as this, and Philip IV. 
became forthwith the owner of the pearl of 
Gorgibus. 

The inventory of 1789 shows that the crown of 
France possessed at that time pearls to the value of 
$186,000, among which occurred — 



PRICE OF PEARLS. 1 97 

isl. A round virgin pearl of a magnificent 
orient, weighing about 27 carats, and estimated at 
$37,200. 

2d. Two pear-shaped pearls, finely formed, 
and of a very beautiful orient, weighing both to- 
gether S7ih carats, and estimated at $55,800. 

3^. Two other pairs of pearl pendants, weigh- 
ing together 99xV carats, estimated at $11,904. 

There is also a magnificent pearl, which was 
brought from Berlin by the first Napoleon, and 
which was exquisitely mounted in a breastplate by 
Lemonnier. 

When the Princess Royal of England was married 
to Prince Frederick William of Prussia she received, 
among other objects of jewelry, a magnificent neck- 
lace formed of thirty-two pearls. It is said that 
the pearls are not all of the first choice, but the 
necklace is valued at $93,000. 

PRICE OF PEARLS. 

Of all the substances employed in jewelry the 
pearl is the one whose value it is the most difficult 
to establish, because it depends upon so many 
variable conditions of size, form, and colour. 

The table given here is one which was made by 
M. Harry Emanuel, to show the price of pearls 
of the first choice in 1 867 : — 



198 



PRECIOUS STONES. 



A Pearl of 3 grains, 
» 4 

5 
6 



4"6s 
7 62 

12 90 
1934 

37 57 
5617 
7030 
93"74 
i40'6i 
186 93 
281 23 
393 '76 



1865. 
to $3 '34 
to s'95 
to 9 '67 

to 13 95 
to 23 "So 
to 4222 
to 7030 
to 84-25 
to 140 61 
to i86"93 
to 223 20 
to 337 59 
to 468 '90 



$3-90 

5 95 

8 55 

IS 06 

21 57 

4687 

65 '47 

8425 

93 74 

i4o'6i 

i86"93 

281 23^ 

39376 



i8(57. 
to 64*27 
to 7 44 
to io'78 
to 17 '129 
to 35-85 
to 51-52 
to 74 95 
to 93-74 
-to 140 '61 
to 186-93 
to 234-36 
to 337-59 
to 468-90 



Besides the individual value which pearls possess 
in common with all other precious stones, and which 
is expressed in the preceding table, they have 
another very important one, which we may call 
associative value. Thus it happens, that two pearls 
of the same form, the same size, the same colour, 
&c., are worth a much higher price, if sold together, 
than when sold apart. A necklace, in which the 
pearls have been chosen from a great number, will 
be held at double the value of a necklace where the 
pearls have been picked from a smaller number, 
even when the individual value of the pearls is 
identical in both. In the first case the harmony 
will be complete ; while in the second case the eye 
will detect a break in the shades in passing from 
one pearl to another. 



CORAL. 
Coral is a submarine production secreted by ani- 



CORAL. 199 

mals forming one little tribe in the grand class of 
polypi. 

The colour of coral follows numberless gradations, 
from an intense red to a complete white. Its com- 
mercial value varies enormously according to its 
colour, the rose tints being the most esteemed. 
Different varieties are named according to the pre- 
cise shade of colour, as "6cume de sang," "rose," 
"fleur de sang," &c. One hundred shades of red 
coral are distinguished at Marseilles. 

Until the eighteenth century it was believed that 
coral was a small tree living and developing itself 
under the sea. It was only in 1727 that a French- 
man, Peyssonnel, established its real nature, show- 
ing that the flowers of this tree were radiated 
animals, and that the coral was gradually formed by 
them. 

Coral is fixed to the solid body which it rests 
upon by a kind of conical outspread foot. The 
nature of the support would seem to be a matter of 
indifference, so long as it is solid. The stems of 
coral are directed often in an opposite direction to 
those of plants, inasmuch as, being attached to the 
under side of rocks, they grow downwards. 

The coral that is known in commerce presents 
itself in the form of little trees more or less branched; 
but in the living coral all the branches are covered 
with a sort of pale-coloured fleshy rind, glossy and 



200 



PRECIOUS STONES. 



polished, showing at its surface a great number of 
cells, each one of which incloses a polype. These 
very elegant little animals are what were taken for 
the flowers of coral. 

Fig. 86 shows the polypi of the coral in different 
degrees of expansion. 




Fig. 86. — Polypes of Coral in different degrees of development. 

It will be seen that their eight extended tenta- 
cules, pointed and incised along their edges, joined 
to the completely white colour of the animals 
themselves, present an ensemble which a century 
or two ago might well be taken for a flower. 

Stripped of its coating, the coral shows a great 
number of parallel, longitudinal, and very often 



CORAL. 20 1 

sinuous striae, stretching from one end to the other 
of the axis. Its texture is extremely compact, this 
being precisely that which permits it to take a per- 
fect polish, and gives it a great part of its value. But 
this texture is not homogeneous; on the contrary, 
it is perfectly organized. To be convinced of this 
we have but to break or cut a branch of coral per- 
pendicularly to the axis, and to submit the part 
left bare to the action of an acid. The different 
parts will be unequally attacked, and a radiated 
texture becomes at once apparent. 

Coral exists probably in all the seas of warm and 
temperate regions, but the Mediterranean furnishes 
to commerce the greater part of this product. 

To gather it there has been for a long time used 
a sort of dredge called salabre, formed of two pieces 
of wood or iron, disposed in the form of a St. 
Andrew's cross, upon the extremities of which nets 
are fastened to receive the coral detached by the 
reiterated blows of the instrument. 

There are also, as in the search for pearls, divers 
who plunge to a considerable depth to gather this 
beautiful production. But already the modern 
appliances for exploring the sea-depths have been 
employed with complete success to the gathering 
of coral. 

There enters into the composition of coral 88 to 
100 parts carbonate of lime, a little magnesia, 



202 PRECIOUS STONES. 

some traces of organic matter, and about i part to 
the I oo of oxide of iron. 

Coral possesses a very interesting property, 
which, beyond doubt, contributed to elevate it to 
the exceptional rank that it has occupied in medi- 
cine, even to the nineteenth century. Certain per- 
sons cannot wear against their skin any objects of 
coral without discolouring them, and this pheno- 
menon is general among all invalids. The ancients 
asserted that if a person wearing a necklace of coral 
was on the verge of an illness, the coral showed dis- 
coloration before the least consciousness was felt 
of the approaching malady. 

Naturalists and chemists have of course inquired 
what is the nature of this singular colouring matter 
that is so exceedingly impressionable.^ So far, the 
only colouring substance which chemistry has de- 
tected in coral is oxide of iron, one of the most fixed 
in nature, and one which, under the circumstances,, 
cannot enter into new and colourless combinations ; 
consequently the problem has not yet reached a 
solution. 

AMBER. 

Amber has been known from earliest antiquity. 
The celebrated founder of the Ionian school of 
philosophy, Thales, who lived 600 years before 
our era, speaks of the property which, above all, 



AMBER. 203 

contributed to render it celebrated — that of attract- 
ing light bodies when it was rubbed. It is from the 
Greek name of amber, electron, that our modern 
term electricity is derived. 

To explain the origin of amber, the Greeks had 
one of those graceful traditions characteristic of the 
young and marvellous genius of that people. They 
said that the sisters of Phaethon, weeping for the 
death of their brother, were changed into poplar 
trees upon the banks of the Eridanus (Po), and 
that their tears were transformed into amber. 

It is to this legend that the tender and har- 
monious poet of the Metamorphoses alludes when 
he says: — 

" Stillataque sole rigescunt 
De ramis electra novis, quae lucidus amnis 
Excipit et nuribus mittit gestanda Latinis." 

"The juices distilling from these new trees, 
solidified by the sun, are received by the shining 
river, and borne as ofiferings to the brides of Italy." 

Chemical analysis shows that there are in 100 
grammes of amber 81 grammes of carbon, y^o of 
hydrogen, 675 of oxygen, and some traces of clay, 
alumina, and silica, amounting altogether to about 
3 grammes. 

This is exactly the composition of resin; indeed 
amber is itself a resin. 

" Amber," said Pliny, " trickles from the pith of 



204 PRECIOUS STONES. 

certain trees resembling pines." This quotation 
proves that the Roman naturahst considered amber 
as a contemporary production. He was right so 
far — amber is a resin ; but it is a fossil resin. ' 

The places most rich in amber are the borders of 
the Baltic Sea, between Dantzic and Memel ; it is 
found also in Denmark, in Norway and Sweden, in 
Poland, France, and England, and in different parts 
of Asia and America. 

Wherever amber is found it is associated with 
lignites. It is nearly certain that the resinous trees 
which produced these combustibles secreted amber, 
since it is not rare to find fragments of amber 
lodged in the midst of beds of lignite. 

The presence of organized bodies, and particu- 
larly insects imprisoned in amber, was well known 
to the ancients, and is mentioned by the poet 
Martial in particular. 

The illustration given here (Fig. 87) shows 
a lizard embedded in a piece of amber. The origi- 
nal fragment of amber belonged to the collection of 
Kircker, and was presented to him by the Duke of 
Brunswick. 

The amber which is most esteemed is translucid, 
and of a beautiful lemon yellow ; but there are also 
varieties semi-opaque, and one of a pale yellow 
with veins and spots of dead-white that is much 
esteemed. 



AMBER. 205 

Amber is worn as an ornament principally in the 
East, where it is cut into beads, and threaded as 




Fig. 87. — Lizard imprisoned in a fragment of Amber. 

necklaces. In western countries it is prized merely 
as serving to fabricate small objects of art, especially 
the mouth-pieces of pipes and cigars. This latter 



206 PRECIOUS STONES. 

usage in the East is justified by the prevalent be- 
Hef that amber never will allow the transmission of 
any infection. This of course would be a highly 
valuable quality, but unfortunately there is nothing 
to prove its existence. 

Lumps of amber are generally very small, but 
occasionally a piece is obtained of considerable 
size; as, for example, a specimen of amber in the 
Royal Museum at Berlin, which weighs i8 pounds. 

Amber is wrought on the turner's lathe by steel 
instruments, and polished on a leaden wheel with 
pumice-stone and water. 



JET. 



Jet, a beautiful black substance, is in point of 
fact a lignite produced by the decomposition of 
resinous vegetation buried in the earth thousands of 
ages before the historic times. Yet in mines of 
lignite jet is rare. 

The hardness, the fineness, and the compactness 
of its tissue probably result from the peculiar 
nature of the trees from which it has arisen. How- 
ever this may be, it is the union of these qualities 
that render jet capable of receiving a very brilliant 
polish, and assert its place as a valuable object of 
jewelry. 

Jet is found in all places where amber exists,.. 



JET. 207 

and in many localities also where amber is not 
found. 

Jet was formerly much more highly valued than 
at present In the last century, Aude, in France, 
alone employed 1200 workmen on this substance. 
At Whitby, in Yorkshire, jet is still the object of 
a considerable industry. But the imitations of 
this substance have largely taken its place; even 
the poor imitation of varnished glass is received 
with favour, A much better substitute for it would^ 
be real stones of little value, such as black tour- 
maline, melanite, and obsidian. 

Jet is worked by means of a lathe and horizontal 
sandstone wheels, smooth at the centre, but rough 
at their circumferences, so that the workman may 
cut and polish a stone on the same wheel. 

Among ancient ornaments of jet are some curious 
anklets and bracelets belonging to the early period 
of British history. 

A complete set of jet ornaments was found in 
two stone coffins deposited under the chief entrance 
of Saint Gereon, Cologne, when that church was 
repaired in 1846. They are supposed to have been 
the ornaments of some priestesses of Cybele. 



PART VII. 



Artificial Production of the Diamond. Boron Diamond — Cagniard 
de Latour — Gannal — MM. Despretz and de Chancourtois. 



" The liquid ore he drained 
Into fit moulds prepared, from which he formed 
First his own tools : tlien what might else be wrought." 



Before we give an account of the attempts that 
have been made to produce the diamond by arti- 
ficial means, it is necessary to state a few facts re- 
garding two other simple bodies whose properties 
very closely resemble those of carbon, and which 
have an important bearing on the subject of which 
we are about to speak. These bodies are boron 
and silicon. 

Not only do these bodies present exactly the 
three modifications presented by carbon — that is to 
say, they are either crystallized, graphitoid, or 
amorphous — but the crystallized boron so closely 
corresponds to the real diamond that it has been 
named from analogy the boron diamond. 

Crystals of boron are limpid and transparent ; 



BORON DIAMOND. 209 

sometimes coloured garnet-red, and sometimes 
honey-yellow, by the presence of foreign matters. 
Their refrangibility can only be compared to that of 
the diamond, and they present the same effects of 
reflected and refracted light. They possess the 
quality of hardness, too, in such a degree as to 
scratch the oriental ruby and corundum ; and M. 
Froment has used a crystal of boron to scratch the 
surface of a diamond. 

The cutting of the diamond with powder of boron 
was attempted by M. Voorzanger, of Amsterdam, 
with entire success ; only that a larger quantity was 
used than would have been necessary of diamond- 
dust, and the work was accomplished more 
slowly. 

The same success attended the cutting of an ex- 
ceedingly hard diamond in the collection of the 
Normal School at Paris. Its angular edges, and a 
furrow which marred it, were removed by a wheel 
covered with powder of boron. M. Guillot, who 
directed the experiment, confirmed the observation 
of M. Voorzanger concerning the superlative quali- 
fications of boron-dust for cutting and polishing 
diamonds. 

It has been further observed that the greater 
number. of the powerful agents at the disposal of 
modern chemistry are without action upon boron. 
" It is," says M. Malaguti, ** the most unalterable of 

14 



2IO PRECIOUS STONES. 

simple bodies ; and if the day comes when it can 
be obtained in large crystals, it may replace the 
diamond^ 

Boron is extracted from boric acid, a production 
elaborated by nature in the depths of the earth, 
and. whose appearance at the surface is one of the 
curiosities of natural chemistry. 

In certain volcanic districts of Tuscany jets of 
hot steam, mixed with carbonic acid, nitrogen, 
hydrochloric acid, &c., and also a small quantity of 
boric acid, issue from openings in the soil called 
soffioni ox f Ulnar olles. Round these soffioni circular 
basins of various diameters are constructed, into 
which the water of neighbouring springs is con- 
ducted. The gaseous jets, forcing their way through 
the water, impregnate it with the boric acid, the 
quantity held in solution being increased by letting 
the water flow through a series of basins, in each of 
which it receives an additional supply of the acid. 
When it is sufficiently charged with the acid it is 
admitted into the final reservoir, where it is allowed 
to stand for a time and deposit its earthy particles. 
The clear solution is now run off, concentrated in 
boilers by the heat of the jets themselves, and the 
acid obtained by evaporation. 

The manner in which MM. Deville and Voehler 
obtained crystallized boron, once so difficult to ob- 
tain, is as follows : — 



BORON DIAMOND. 211 

Into a charcoal crucible 80 grammes of alur 
minium is introduced in large morsels, and 100 
grammes of boric acid reduced to fragments. This 
crucible is placed with charcoal paste in a crucible 
of plumbago, and the whole is subjected to the 
act^n of heat in a furnace producing a heat capable 
of easily melting pure nickel. This temperature is 
kept up for five hours ; and when, after the cooling, 
the crucible is broken open, it is found to contain two 
distinct layers. The lower layer is vitreous, and 
formed of boric acid and alumina; the other is 
metallic, gray, and cavernulous, and is roughened 
and impregnated throughout its whole mass with 
little crystals: this is crystallized boron. 

The mass in which these crystals are distri- 
buted is formed principally of aluminium, but it 
contains also variable quantities of iron and of 
silicon. 

The whole is boiled in a lixivium of soda, of 
medium concentration, when the aluminium dissolves. 
That which remains is boiled with hydrochloric 
acid, and the iron is thus removed. The part not 
yet attacked is treated by a mixture of hydrofluoric 
acid and nitric acid, which removes the last traces of 
silicon. The boron, which has not experienced the 
slightest action under the influence of the preceding 
agents, remains as the definitive residue. 
. The boron thus obtained, however, is not per- 



212 PRECIOUS STONES. 

fectly pure; its analysis by M. Deville gives the 
following results: — 

Boron, Sg'i 

Aluminium, 6'j 

Carbon, 4'2 



lOO GO 



It is very remarkable that this proportion of car- 
bon (more than 4 to 100) does not prevent the 
boron from being transparent; and what is still 
more extraordinary is, that the boron becomes 
more and more transparent as the proportion of 
carbon increases. 

M. Deville's conclusion is therefore inevitable, 
viz. that it is nearly certain that the carbon con- 
tained in the crystallized boron is present there in 
the state of diamond. 

We perceive, then, that boron is worthy of the 
utmost attention, as being capable of affording a 
jj^^««/ diamond, and for its possible concurrence in 
the artificial production of real diamonds. 

The properties of silicon being the same as those 
of boron, we need not pass them in review here. 

ATTEMPTS TO PRODUCE THE DIAMOND. 

Two hypotheses arrest consideration in examining 
the probable origin of the diamond ; the first con- 
ceives of carbon as having been melted by a strong 
heat, and the diamond having crystallized in an 



ARTIFICIAL DIAMOND. .-2 1 3 

excess of liquid; the j-^c^/^^ supposes a body capable 
of dissolving carbon, and allowing it to crystallize 
by evaporation. 

Another theory was advanced by Sir David 
Brewster concerning the origin of the diamond. 
Hg supposed that this beautiful gem is of organic 
origin, and he was led to this opinion by examining 
the diamond microscopically, when he discovered 
certain striations and dispositions that resembled 
the fibres of organic substances, and particularly of 
certain species of wood. 

These are but suppositions, however, and we 
really know nothing for certain regarding the origin 
of the diamond. The most we can say is that it is 
very- improbable the diamond was produced under 
the action of a high temperature. 

The knowledge of the chemical composition of 
the diamond is so recent that all the experiments 
made with the least chance of success to reproduce 
it have occurred within the last half century. 

In 1828 two interesting experiments were made 
nearly at the same time by Cagniard de Latour 
and Gannal; De Latour presented his results to 
the Academy of Sciences, Oct. 10, 1828; and those 
of Gannal were presented the 23d of November the 
same year. 

Cagniard de Latour sent to the Academy of 
Sciences ten tubes containing a number of light- 



214 PRECIOUS STONES. 

brown crystals, some of which were of consideriable 
dimensions. They were brilliant, transparent, and 
harder than quartz. They were examined by MM. 
Thenard and Dumas. 

Submitted to an intense heat in contact with the 
air, the crystals experienced not the slightest 
change, a proof sufficient in itself that they were 
not of the nature of the diamond. Besides, not- 
withstanding their considerable hardness, they were 
easily scratched by the latter gem. The conclusion 
of the academical savants was, that the pretended 
diamonds were merely silicates or artificial precious 
stones. 

The experiments of Gannal gained more renown. 
Specimens of his productions were sent to M. 
Champigny, director of the workrooms of the jewel- 
ler Petitot, who examined them with care; and 
having satisfied himself that they scratched steel, 
and could be scratched by no metal, that they were 
of pure water, and displayed a brilliant lustre, con- 
cluded that these little bodies were nothing else 
but diamonds. This declaration, emanating from 
a man well versed in the special trade, created an 
excitement and even a panic in the diamond trade. 

The process by which Gannal obtained his dia- 
monds was very simple. 

He introduced carbon disulphide and water into 
a matrass, with morsels of phosphorus, which in the 



ARTIFICIAL DIAMOND. 



215 



disulphide dissolved rapidly. He hoped that this 
phosphorus would slowly absorb the sulphur of the 
disulphide of carbon, and that the carbon, reduced 
gradually to an elementary state, would crystallize. 
Carbon disulphide and water will not mix to- 




Fig. 88, — Gannal's arrangement for the Production of the Diamond. 



gether; and the former being much the most dense, 
occupied the bottom of the vase. 

Between the two layers a pellicle formed which 
strongly reflected the light when exposed to it. 
In time this layer was augmented; and, at the 
end of several months it was composed of a con- 
glomeration of little solid bodies, which were sepa- 
rated from the liquid by filtration through a 
chamois-skin. These little bodies were the cr)^stals 
pronounced by M. Champigny to be diamonds — ^an 
opinion that was utterly erroneous. How they 



2l6 PRECIOUS STONES. 

came there is not known, but it is probable that 
either the substances made use of were not pure, 
or that some foreign body or bodies had found 
their way into the matrass. 

The man who has most effectually disturbed the 
slumbers of the possessors of diamonds, by agitating 
the question of their artificial reproduction, is M. 
Despretz. 

This patient and persevering chemist organized a 
series of experiments founded at first on the belief 
that the diamond was formed by igneous means. 

In his first attempts, accordingly, he submitted 
carbon to the action of the most intense heat that 
he could possibly command; having for this pur- 
pose united and arrayed all the Bunsen piles that 
he could procure at Paris, and so obtained a current 
of prodigious intensity. 

. The carbon was immediately reduced to vapour, 
and was soon deposited in the form of fine dust on 
the walls of the vessel in which it was contained. 
M. Despretz would have it that the carbon had 
been volatilized ; and no one who attended his lec- 
tures at the Sorbonne can forget the profound dis- 
dain with which he would exhibit the glass globe 
all blackened interiorly, and exclaim, "And yet 
there are people who maintain that carbon cannot 
be volatilized!" With all due respect for this emi- 
nent opinion, it is probable that the carbon was not 



ARTIFICIAL DIAMOND. 



217 



volatilized, using that word in its common accep- 
tation, but that it was merely molecularly dis- 
sociated. However this may have been, the results 
were completely inadequate to the production of 
the diamond. 

Violent means having failed, M. Despretz changed 
the system. For the currents of the pile, intense 




Fig. 89. — M. Despretz's arrangement for the Production of the Diamond. 



and incessant, he substituted currents of induction, 
intermittent and feeble; and in place of continuing 
their action for several hours, maintained them in 
activity during entire months. 

The results of his new experiments M. Despretz 
submitted to the Academy of Sciences. 



2l8 PRECIOUS STONES. 

He made use of a glass vessel similar and simi- 
larly fitted up to that known as the electric egg 
(see Fig. 89). To the lower rod he attached a 
cylinder of pure carbon, an inch or so in length, 
and nearly half an inch in diameter. To the upper 
rod he affixed a bundle of fine platina wires. He 
now exhausted the air from the balloon, and the 
distance from the wire to the carbon being about 
two inches, he then passed an inductive current by 
Ruhmkorff's apparatus. 

The luminous arc was suffused with a red tint 
on the side next the carbon to a short distance 
from the platina; the part which enveloped the ex- 
tremity of the platina wires was a violet-blue. 

This disposition of the apparatus was constantly 
maintained; and the experiment lasted more than 
a month without interruption, excepting the time 
necessary to recharge the pile. At the completion 
of this time a slight black layer of carbon had been 
deposited on the wires. This layer, viewed through 
a magnifying glass, presented nothing very dis- 
tinct; but to the compound microscope, with mag- 
nifying power of about thirty diameters, it offered 
several interesting features. Upon the wires, and 
especially upon their extremities, certain separate 
points were discoverable, which appeared to belong 
to octahedral crystals. 

An experienced crystallographer confirmed this 



ARTIFICIAL DIAMOND. 219 

view, and recognized octahedrons, both black and 
white, the black being truncated at their ex- 
tremities. 

In another experiment M. Despretz fixed a cylin- 
der of pure darbon to the positive pole of a weak 
Dafiiell pile, and a platina wire to the other pole; 
he then plunged both poles into slightly acidulated 
water. The experiment lasted two months; the 
negative wire or pole became covered with a black 
coating, but nothing was discovered in it under the 
microscope. 

The products of the experiments were then sent 
to M. Gaudin to test upon hard stones. He proved, 
in the presence of M. Despretz and others, that, 
mixed with a little oil, the substance which had 
enveloped one of the twelve platina wires suf- 
ficed to polish in a very little time several rubies. 
The black powder deposited in the water served to 
give similar polish, but it required longer time. As 
it is known that the diamond is the only substance 
that polishes the ruby, M. Gaudin did not hesitate 
to consider both these substances as the powder of 
the diamond. 

Two conclusions may be derived from the facts 
we have just stated : ist, that it is probable that 
the diamond is not of igneous origin ; 2d, that M. 
Despretz has really obtained artificially the true 
diamond. This is the opinion of men of the 



220 PRECIOUS STONES. 

highest authority, and in particular that of M. 
Dufrenoy, 

The last contribution made to the interesting 
question of the production of the diamond was 
made by M. de Chancourtois. He based his theory 
upon phenomena presented by the solfataras, where 
sulphuretted hydrogen under the influence of a humid 
oxidization, is transformed slowly into water and 
sulphurous acid, and deposits crystallized sulphur. 
He proposed to produce upon carburetted hydro- 
gen reactions of the same order. Under the in- 
fluence of a humid oxidization all the hydrogen is 
transformed into water, one part only of the carbon 
into carbonic acid, and he thought it possible that 
the remainder, being slowly deposited, might crys- 
tallize and form diamonds. As a means of verifi- 
cation, M. de Chancourtois suggested the very slow 
passage of carburetted hydrogen in a mass of sand 
containing putrescible matter. Five years have 
elapsed since the expression of these views, and it 
does not appear that they have yet led to any 
positive result. 

The question still remains — Is there any reason- 
able probability that the diamond will yet be pro- 
duced artificially.'' This question we must an.swer 
in the affirmative. When it is considered how per- 
fectly substances much more complex in com- 
position, and complicated in crystalline constitution, 



ARTIFICIAL DIAMOND. 221 

have been artificially produced; when it is con- 
sidered, too, what definite results were furnished by 
the second series of the experiments by M. Despretz 
— for in such a case the size of the crystals is a 
matter of indifference — there seems to be no reason 
for serious doubts of the possibility of the artificial re- 
production of the diamond. Undoubtedly it will be 
a discovery from which the diamond-merchants and 
owners of diamonds will have much to suffer; but 
in this, as in other cases, the loss that will fall upon 
a small section of the community will be outweighed 
a thousand times by the advantages which arts and 
industry in general will derive from the discovery. 



PART VIII. 



Artificial Production of real Precious Stones, Results obtained, 
Becquerel, Ebelman. Gaudin, Henri Sainte- Claire Deville, 
De Sinarmont. Daubrie. Durocher. Sainte- Claire Dez'ille and 
Caron, dr'r. 



" Beset with emeralds 
And diamonds, with sparlcling rubies red 
In checkerwise, by strange invention." 



We have seen that the elementary constituents of 
precious stones must have existed once in a con- 
dition that allowed them to move freely; and that 
this condition was obtained by one of three 
general methods — 

1st. — Direct fusion of the substance by a suf- 
ficient heat. 

2d. — Dissolution at variable temperatures of the 
mineral substance in a foreign body, and complete 
or partial volatilization of the dissolvent ; or crys- 
tallization without evaporation under the influence 
of natural forces, either alone or aided by heat, 
electricity, &c. 

3d.— Prior reduction into vapour of substances 
destined to react upon each other. 



ARTIFICIAL PRODUCTION. . 223 

To the first method belong the results of the 
observations of Mitscherlich upon the mineral 
species which are naturally produced in furnaces 
where metals are reduced ; the direct reproduction 
of several minerals by Berthier; iand, above all, the 
fusion of alumina and of silica, by M, Gaudin. 

The second method comprehends the remarkable 
results of Ebelman; that which M. de Senarmont has 
employed, but in which intervenes a new element, 
that of a very strong compression ; and lastly, that 
of M. Becquerel, but with still another element, the 
action of a feeble electric current. 

The third method includes the results obtained by 
MM. Daubree, Ebelman, Durocher, Henri Sainte- 
Claire Deville and Caron, &c. 

FIRST METHOD. 

If any one should say — I am going to produce a 
fire of enormous power, without employing any 
substance but water, he would run the risk of being 
considered a fool, since fire and water have always 
been considered the antipodes of one another. 
Even modifying the announcement, and saying — 
I am about to produce an intense fire by means of 
elements derived exclusively from water, hardly 
makes the proposition appear more plausible, yet 
nothing can be more rigorously exact. 



224 PRECIOUS STONES. 

Water is composed of two bodies, which, in the 
present state of knowledge, are considered simple: 
they are two gases — one called oxygen, the other 
hydrogen. If a mixture of these two gases is made, 
and if to this mixture an ignited body is applied, 
the two gases combine and form water; but at the 
same time there is a production of vivid light, and a 
development of a great quantity of heat. These 
two effects attain their maximum when the mixture 
is formed of one volume of oxygen and two of 
hydrogen. 

If, instead of forming the mixture immediately, 
we arrange so that the two gases arrive separately, 
in two uniform and continuous streams, at an orifice 
of small diameter, and if an ignited body is applied 
to this orifice where the gases meet and combine, 
the mixture takes fire. As the two gases are con- 
stantly renewed at the orifice, the combustion is not 
interrupted ; and a jet of flame is attained analo- 
gous to that of a gas-burner. It gives out little 
light, but develops an exceedingly elevated tem- 
perature. The contrivance is called the oxyhydro- 
gen blowpipe, and is in common use among 
chemists and others. 

By aid of this instrument M. Gaudin melted 
silica and alumina, and artificially reproduced the 
corundum. 

The corundum, as we have seen, is crystallized 



ARTIFICIAL PRODUCTION. 22$ 

alumina. To obtain it M. Gaudin heated ammonia 
alum and potash alum: the enormous heat de- 
veloped by his apparatus volatilized the potash, and 
the alumina crystallized. Rubies were obtained in 
this manner; and M. Dufrenoy has found in these 
pipductions the rhombohedral form, and the triple 
cleavage proper to the corundum. Finally, M. Mala- 
guti has established, by the analysis of these crys- 
tals, that they contain 97 to 100 parts of alumina, 
and 2 of silicate of lime ; a composition analogous 
to that of the ruby. 

The experiments of M. Gaudin date back to 1837; 
this date gives the priority to this ingenious phy- 
sicist for the artificial production of the corundum. 

It should nevertheless be noted that more than 
ten years before the work of M. Gaudin, a man who 
has left a deep impress on science, Berthier, basing 
his experiments upon chemical proportions, repro- 
duced a great number of minerals, such as peri- 
dote, pyroxene, &c., by bringing their elements 
together at a high temperature. 

SECOND METHOD. 

In the year 1823 M. Becquerel, one of the most 
eminent of French physicists, formed the idea of 
using the currents of the voltaic pile to determine 
combinations, and not merely decompositions. 

15 



226 



PRECIOUS STONES. 



Instead of employing powerful currents, such as 
were used to produce decomposition, he applied to 
his purpose very feeble currents, and the results ob- 
tained surpassed his expectations. 

The simple apparatus which he used is shown in 
Fig. 90. It is a tube curved in the form of the 
letter U. The curved part is filled with clay, to 
prevent the liquids contained in the branches from 




Fig. 90. — Voltaic Apparatus of M. Becquerel for the Production of Crystals. 



flowing together, without interfering with the pro- 
duction of molecular actions and transports. The 
two liquids are, moreover, placed in direct com- 
munication by means of a metallic wire. 

One of the substances reproduced by M. Bec- 
querel was the sulphide of silver crystallized. 

In the left branch of his tube he placed a satu- 
rated solution of nitrate of silver, in the right branch 



ARTIFICIAL PRODUCTION. 227 

a solution of sulphide of potassium, and established 
a communication between the two liquids by the 
aid of a silver wire. Silver was deposited on the 
left-hand wire, and crystals of the double sulphide 
of silver and potassium on the right ; but the sul- 
phide of potassium being rapidly destroyed by the 
nitric acid, there remained on the wires in the clay, 
and on the walls of the tube, perfectly defined crys- 
tals of sulphide of silver, presenting all the charac- 
teristics of natural crystals. As the current was 
very weak, the crystals took long to form ; some of 
them from seven to eight years. 

The method by direct fusion could only be ex- 
pected to produce fusible minerals. The electric 
method had given neither a silicate nor an alumi- 
nate ; and, as crystallized bodies belonging to these 
classes are by far the most important, Ebelman 
set himself to solve the problem of their pro- 
duction. 

Every one knows that if crystalline substances — 
such as salt, for instance — are dissolved in water, 
and the solution is allowed to stand in the open 
air, the water will disappear after a time, and the 
substance that was dissolved in it will be left in the 
shape of solid crystals. 

Reasoning by analogy, then, Ebelman came to 
the conclusion that he must find some body capa- 
ble of dissolving infusible combinations without 



228 PRECIOUS STONES. 

contracting combinations with them, and capable of 
being reduced to vapour at a still higher tem- 
perature. 

Experiment taught him that boric acid possessed 
the requisite properties in a high degree. 

Being director of the manufactory of porcelain at 
Sevres, he profited by the high temperatures de- 
veloped in the furnaces to make some very in- 
teresting experiments, which were afterwards pro- 
duced with still greater success at the continuous 
fires of furnaces placed at M. Ebelman's disposal 
by M. Bapterosses, fabricator of buttons of ceramic 
paste. 

Mixtures in proportions corresponding to the 
composition of the stones to be produced were 
placed in capsules of platina along with boric acid, 
and the whole was submitted to a high temperature. 
The boric acid first melted, and afterwards volati- 
lized, and, as Ebelman had anticipated, the sub- 
stances that it held in solution crystallized. 

In this way he produced the spinel ruby so per- 
fectly that it could not be distinguished by Dufr6- 
noy from the natural stone. This was effected by 
subjecting a compound consisting of proper pro- 
portions of alumina, magnesia, the green oxide of 
chromium and boric acid to a high temperature in 
the muffle of a furnace for eight days. He obtained 
crystals measuring O'iq/ inch on a side. 



ARTIFICIAL PRODUCTION. 229 

The method employed by M. Senarmont is the 
method of dissolution by means oj water. It is, 
without doubt, the method employed by nature in 
caverns and calcareous crevasses, where, after a 
number of years, often very small stalactites of 
cr)jstallized carbonate of lime are produced. These 
productions, and the phenomena of thermal springs, 
where the pressure and heat are often very high, 
and the deposits of mineral waters, suggested to M. 
de Senarmont the method of his experiments. 

He introduced into the most resisting sort of 
glass tubes the elements of the substances he wished 
to produce. He placed together gelatinous silica, 
and a body susceptible of furnishing carbonic acid 
by the action of heat (bicarbonate of soda), and 
having closed the tubes at the lamp, submitted 
them to variable temperatures and variable 
pressure. 

By this process M. Senarmont obtained a great 
number of crystallized minerals, the most remark- 
able of which was quartz. 

THIRD METHOD. 

M. Daubree had pointed out in 1841 the prin- 
ciple upon which, in 1849, he produced artificially 
a certain number of crystallized minerals. The 
idea was to compel the vapour of water to react at 



230 PRECIOUS STONES. 

a certain temperature upon the metallic fluorides, 
chlorides, &c., themselves brought to the state of 
vapour by the action of heat. 

In these conditions a double decomposition is 
produced, and metallic oxides are formed, which 
crystallize. 

Results of the same order are produced by intro- 
ducing only the vapours of the metallic combi- 
nations destined to give rise to new bodies. 

M. Daubree obtained by this process a great 
number of species perfectly crystallized; among 
them the oxide of tin and quartz. Instead of 
making the vapours react upon each other, he 
made them react upon solids, and the results were 
no less satisfactory. It is by the employment of 
this method that M. Daubree has produced first 
the apatite, and a compound having a close analogy 
to the topaz; and more lately has, by the use of 
the chlorides of silicon and aluminium, produced 
crystallized silicates and aluminates. 

M. Durocher has obtained a great number of 
crystals by a method similar to that of M. Daubree. 
The only essential differences between their pro- 
cesses is that Durocher used soluble combinations 
which pertained each one to the elements of the 
mineral he wished to crystallize, and Daubree in- 
terposed vapours of water as a means of decom- 
posing the generating vapours. 



ARTIFICIAL PRODUCTION. 23 I 

The latest experiments in the reproduction of 
crystals, and particularly of precious stones, have 
been made by MM. Deville and Caron. The 
method employed by these chemists is founded 
upon the same principle as those of Daubree and 
Du*ocher; but the agencies employed by them are 
incomparably more powerful, and the results which 
they have obtained more brilliant. 

With the enormous temperature developed by 
the furnaces of Deville and Caron ordinary cru- 
cibles could not be used: they melted like lead. 
The crucibles which they used were made of lime. 
Anybody can make them, and they are absolutely 
fireproof 

Among the principal results obtained by the ex- 
periments of these chemists were crystals of white 
corundum, rubies, and sapphires. 

The crystals of corundum, nearly two-fifths of an 
inch in length, exhibited all the crystallographic 
and optical properties of the natural corundum. 
The rubies, obtained very nearly in the same way, 
had the violet-red tint of the natural ruby conveyed 
to them by the oxide of chromium, which furnished 
also, in a different proportion, the blue of the 
sapphires. Sometimes, in the experiments of De- 
ville and Caron, red rubies and sapphires of the 
most beautiful blue were obtained side by side. 

A similar experiment produced specimens of 



'232 PRECIOUS STONES. 

cymophane identical in all respects with the cymo- 
phane found in America, in small but very perfectly 
formed crystals. 

The processes we have just described are all dis- 
tinguished by special features, though depending, 
as already mentioned, on a small number of laws. 
It is probable that nature has employed them by 
turns. In any case they suffice to explain the for- 
mation of the greater number of crystallized mineral 
substances at present known. 



PART IX. 



False Preciotis Stones. 



' Art, aping Nature, eager to deceive. 
Has learnt to imitate the jewel true 
With lying glass, and thus beguile the view. 
Hence hard the real gems from false to know. 
When pastes with imitative colours glow. 
Their boasted virtues soon as tested fail. 
And hence discredit does the true assail. 
Yet the true gem, by sages duly blest. 
In wondrous works its power will manifest." 



Under the name of false precious stones, there 
are two kinds of productions which are essentially 
different — the one natural, the other artificial. 

The first comprehends stones sufficiently hard 
to resist the file; they are generally quartz, either 
hyaline or variously coloured. 

The second consists of artificial compositions of 
the nature of glass. 

There is an intermediate order, the productions 
belonging to which, if well executed, are especially 
calculated to deceive, and are used to great extent 
in the East Indies. They are called semi-stones, 
or doublets. 



234 PRECIOUS STONES. 

FALSE PRECIOUS STONES OF THE NATURAL 
KIND. 

It is of some importance to examine this subject, 
because there is a prevalent belief that all false 
stones necessarily have glass as their base, and are 
consequently of little hardness. People often say, 
when their rubies or their topazes are declared false, 
" But, see, here is a file ; try to scratch these stones ; 
you will not succeed." Very true; but submit any 
piece of quartz to the same test, and the result will 
be the same. 

Since, as we have said, hyaline or variously col- 
oured quartz is very abundant in nature, it is easy 
to procure, at insignificant prices, stones that per- 
fectly resist the file, and show, often in a remark- 
able manner, the whole series of colours that we 
admire in real precious stones. 

Stones of this kind are very abundant in com- 
merce; it might be said that, with few exceptions, 
all those designated as occidental are of this char- 
acter, and possess consequently hardly any value. 

Another deception of the same kind consists in 
passing off a stone of a certain nature and a certain 
value, for another stone of a different nature and a 
much higher value. 

The colourless varieties of sapphire and topaz, 
which in density, in hardness, and in refractive 



FALSE PRECIOUS STONES. 235 

power differ but little from the diamond, are fre- 
quently cut into roses and brilliants, and sold for 
diamonds. A proof of this fact is furnished by the 
commercial price of the colourless topaz, which is 
much greater than it could obtain as topaz. It is 
valued in the secret hope that after cutting it may 
be sold for diamonds. 

At the present day there are means — such as the 
scales for determining specific gravity, polariscopes, 
&c. — for distinguishing with mathematical certainty 
the diamond from the sapphire or topaz ; but these 
tests are of modern origin; and in the middle ages 
not only colourless topazes, but those whose tint 
had been removed in different ways, principally by 
the action of fire, frequently passed current for 
diamonds. Nay more than this, under the influence 
of the ideas that then prevailed concerning trans- 
mutation, the successful experimenters believed 
that they had actually transformed rubies and 
topazes into diamonds. 

Cardan furnishes some very curious details on 
this subject. He gives a receipt by which " a limpid 
sapphire of a faint colour" may be boiled in melted 
gold and converted into a true diamond. 

SEMI-STONES OR DOUBLETS. 
This mode of imitating real stones, though vary- 



236 PRECIOUS STONES. 

ing in a great many respects, is generally effected 
by giving the proper shape to a morsel of strass; 
removing from the upper portion of it a certain 
thickness, and replacing this by hard stone in such 
a way as to complete exactly the strass stone, then 
mounting the whole in a setting that completely 
conceals the line of junction of the two stones. 

Doublets are of two kinds: in both the under 
part is strass, but in one the upper part is a plate 
of the real stone; in the other, it is simply hard 
stone, generally quartz, and of no value. 

The invention of this process has been attributed 
to a modern jeweller of Paris, named Bourguignon ; 
but in reality it can be traced as far back as the 
fifteenth century. 

A complete description of the mode of manufac- 
turing doublets is given by Cardan, who has even 
preserved for us the name of the inventor: — 

"A fraud of a very bad character, and one very 

difficult to find out, was employed by Zocolino . 

This venerable personage used to take a thin flake 
of real precious stone, such as carbuncle, emerald, 
&c., when he wished to imitate the carbuncle or 
emerald, choosing such pieces as had but little 
colour, and were consequently very cheap. Under- 
neath he placed a piece of crystal sufficiently thick, 
and united the two parts by means of a transparent 
glue, in which he incorporated a colouring matter 



FALSE PRECIOUS STONES. 237 

in harmony with the stone that he meant to imi- 
tate — brilliant red for carbuncle, green for emerald, 
&c. He concealed the line of junction of the two 
parts by means of the setting ; and to avoid giving 
rise to suspicion, he set them in gold, which was 
not allowed except in the case of real precious 
stones. 

" In this way this magnificent workman deceived 
everybody, even the lapidaries. However, the fraud 
was at last discovered, and Zocolino took refuge 
in flight. 

"It appears that this personage had a peculiar 
disposition for fraud, for he turned his attention 
afterwards to the fabrication of counterfeit money; 
and ended by being condemned to death." 

An examination of the objects adorned with 
precious stones, that have been executed in the 
middle ages, shows that the process described by 
Cardan was not unfrequently employed. 

FALSE PRECIOUS STONES OF THE ARTIFICIAL 
KIND. 

The basis of all false stones of this kind is glass. 

A fixed alkali (soda or potash) and silica heated 
to a red heat will combine and produce glass. 
Alumina, lime, magnesia, &c., may enter into the 
combination with the silica ; but the result in both 



238 PRECIOUS STONES. 

cases is colourless, or what is ordinarily called 
white glass. But if to these substances metallic 
oxides, or metals in a divided state, are added, 
even in minute quantities, the result is coloured 
glass. 

Chemical analysis shows us that the elements of 
glass are found in all vegetables. If, then, a fire 
consumes a certain quantity of wood, gathered to- 
gether at a single spot, vitrifications will be found 
in the residuum. When silicious stones are sub- 
jected to an intense heat, the bases contained in 
the stones and in the cinders combine and produce 
glass. This is what may be seen every day in an 
examination of the interior walls of a lime-kiln or 
brick-kiln. It is evident, then, that the discovery 
of glass belongs to the earliest period of man's 
existence. If it be remarked, besides, that the glass 
thus obtained is always coloured, and therefore in 
harmony with the pronounced taste of primitive 
people for brilliant objects, we understand how 
these vitreous substances produced by conflagra- 
tions and, above all, by the action of fire upon 
silicious stones, must have excited, in the most 
lively manner, the attention of men from the first 
ages of our species. 

Had this book been written a dozen or fifteen 
years ago, it could have furnished but little infor- 
mation on this head ; but, thanks to the researches 



FALSE PRECIOUS STONES. 239 

of archaeologists, and in particular those of M. Bou- 
cher de Perthes — for whom, no doubt, history re- 
serves an exceptional place in its annals — humanity- 
beholds its origin almost instantaneously extended 
far beyond the historic ages, far beyond all tra- 
ditions! A new period, during which man lived 
upon our globe, and which has not until our own 
epoch been suspected, is now revealed in the most 
incontestable manner; and among the remains of 
human industry referable to that remote epoch, 




Fig. 91. — Egyptian Bracelet in Ceramic Paste, with coloured Ornamentation. 

are found objects of coloured glass. It must be re- 
marked that coloured glass is much more easily 
obtained than glass without colour, an(J that the 
latter has been produced with ease only in quite 
modern times. 

Without departing from historic times, but only 
reverting to their most ancient ages, we find that 
the Egyptians understood very early the manufac- 
ture of glass, and especially the coloured glasses. 

The design of an Egyptian vase of blue glass, 
ornamented with white and yellow, is given in Fig. 
92. In quality of material, in form, in elegance of 



240 PRECIOUS STONES. 

ornamentation and harmony of colouring, this vase 
is in no respect inferior to the best productions of 
the present day, and yet it must have issued from 
the hands of the Egyptian workman four thousand 
years ago. In Figs. 91, 93, 94, 95, and 96, the 
objects represented are of ceramic paste. From 




Fig. 92. — Egyptian Vase of Blue Glass, with white and yellow Ornaments. 

an artistic point of view, these objects are of 
no value, but the delicacy of their details is well 
worth notice, especially when we consider that they 



FALSE PRECIOUS STONES. 



241 



must have been moulded when the matter was in 
a soft state. 




^'g- 93- — Egjrptian Moulding in Ceramic Paste. 

In the time of Pliny, the manufacture of false 
stones was far advanced as a branch of industry- 




Fig. 94. — Egyptian Ring, with a Bezel of Ceramic Paste. 

among the Romans. There existed several treatises 

16 



242 PRECIOUS STONES. 

upon the subject; and Pliny declared that it was a 
difficult task to distinguish between the false and 
the true. Not only in Rome were false stones in 
vogue, but, according to Pliny, the Indians coun- 
terfeited jewels with success, especially opals. 

The processes that Pliny was so careful not to 
divulge, were not held sacred with the same scru- 
pulousness by the alchemists of the twelfth and 
thirteenth centuries. Both Albertus Magnus and 
St. Thomas Aquinas refer openly to this subject ; 




Fig- 95- — Egyptian Ring of Gold, with inlaid work of Enamel. 

and the latter in his treatise on the Essence of 
Minerals, states explicitly that there were "men 
who fabricated artificial jewels." Among the pre- 
cious stones counterfeited, he instances the hya- 
cinth, sapphire, emerald, ruby, and topaz. 

At the commencement of the Renaissance the 
fabrication of false stones still continued ; but it was 
not yet separated from much hesitation and experi- 
ment. Cardan proves this in his curious receipts. 

A century later we perceive by the descriptions 



FALSE PRECIOUS STONES. 243 

of Kircher that the industry had greatly advanced. 
To the unburned "brick" of Cardan, in whose cavity 
his mixture for precious stones was heated, excel- 
lent crucibles had succeeded ; special furnaces had 
replaced the brick-kiln ; and in the time of Kircher, 
that_is to say, about the middle of the seventeenth 
century, false stones were no longer manufactured 
according to methods differing for each stone, but 
according to a general formula much the same as 
that followed at the present day. 




Fig. 96. — Egyptian Moulding in Ceramic Paste. 

No other proof is needed than the writings of 
Kircher to dissipate the error that has ascribed the 
invention of strass — a peculiar kind of glass of con- 
siderable refractive power, which forms the base of 
all modern artificial gems — to a workman of that 
name, towards the close of the last century. This 
production was perfectly well known in the middle 
ages; and it was used for exactly the same purposes 
as it is used for to-day — for decoration, and the 
counterfeiting of precious stones. It is distin- 
guished from ordinary glass by the presence of 



244 PRECIOUS STONES. 

about 50 per cent, of oxide of lead among its con- 
stituents. 

There existed in the middle ages, and probably 
had existed among the ancients also, a substance 
called at first amasa, then encausta, and lastly 
smalta, from which last term our modern email 
(enamel) is derived. These were generic expres- 
sions for substances formed of glass and a metallic 
oxide; and the basis employed was certainly a 
kind of strass — that is to say, glass containing a 
great quantity of oxide of lead. 

The improvement made in strass since the middle 
ages is due to our modern chemistry, which fur- 
nishes productions of a perfect purity, otherwise 
the ingredients, and probably their proportions, re- 
main the same ; and the same rule is still observed 
that the longer the fusion is prolonged, the finer 
will be the quality of the strass. According to M. 
Dumas, the strass now employed consists of — 

Silica, 38"2 

Red oxide of lead S3'o 

Calcined potash, 7'8 

Calcined borax, alumina, and arsenious acid, . . . Traces. 

When the strass is obtained very pure, all the 
precious stones may be imitated with it. For this 
purpose it is melted and mixed with substances 
having a metallic base, generally oxides, which, 
combining with the elements of the strass, com- 
municate to it the most varied colours. We add a 



FALSE PRECIOUS STONES. 245 

few details to show how the principal gems may be 
imitated. 

Diamond. — The diamond being colourless, pure 
strass, cut into brilliants and roses, is used to coun- 
terfeit it. 

Ruby. — 1000 parts strass, 40 glass of antimony, 
I purple of Cassius, and i, in excess, of gold. 

Sapphire. — 1000 parts strass, and 25 oxide of 
cobalt. 

Topaz. — Same formula as that of the ruby, with- 
out the excess of gold, and heated for a less time. 

Emerald. — 1000 parts strass, 8 oxide of copper, 
and 0'2 oxide of chromium. 

Amethyst. — 1000 parts strass, 25 oxide of cobalt, 
and a little oxide of manganese. 

Garnet. — 1000 parts strass, and a variable quan- 
tity of purple of Cassius, according to the shade to 
be obtained. 

Aventurine. — For several centuries Venice has 
had the monopoly of the fabrication of aventurine ; 
and even now, it is a Venetian artist, Bibaglia, who 
furnishes to commerce the artificial aventurine that 
is most highly prized. 

Aventurine is a glass the base of which is soda 
ash, lime, and magnesia, coloured yellow by oxide 
of iron, and holding in suspension a large number 
of small particles of oxide of copper. The distri- 
bution of these particles in a regular manner through 



246 PRECIOUS STONES. 

the whole vitreous mass appears to be the chief 
difficulty in its manufacture. 

The dexterity requisite to accomplish this must 
be very difficult to attain, for the profits realized 
from the manufacture of aventurine are remarkably 
large. According to its quality, the artificial gem 
sells for $5 to $15 the pound, while the raw mate- 
rials that enter into the composition of a pound of 
it are certainly not worth a quarter-dollar. 

French chemists— M. Hautefeuille in i860, and 
M. Pelouze in 1865 — have published processes by 
which productions have been obtained equal to 
that of Venice, and, in the latter case, perhaps 
superior. 

The new aventurine of M. Pelouze has a beautiful 
lustre, and a hardness exceeding that of glass and 
ordinary aventurine. It is obtained by melting 
together 250 parts sand, 100 parts carbonate of 
soda, 50 parts carbonate of lime, and 40 parts bi- 
chromate of potassium. It will be seen that by 
this formula the spangles with a basis of copper 
are replaced by spangles with a basis of chrome. 

FALSE PEARLS. 

False pearls are little hollow spheres of glass 
covered internally with a coating imitating the 
orient of natural pearls. Their fabrication com- 



FALSE PEARLS. 247 

prehends two series of operations — the production 
of the sphere, and the introduction of the coating. 

The spheres are produced by the glass-blower, who 
by aid of an enameller's lamp solders the extremity 
of a tube having the proper diameter, and blowis 
into the tube when the substance is of the right 
conristency. In this way very regular little spheres 
are obtained, that serve for the composition of the 
ordinary quality of false pearls. 

In pearls of great beauty the tube employed is 
slightly opalescent, and the glass-blower, besides, 
gives to the little spheres, while they are yet malle- 
able, certain slight perceptible inequalities of sur- 
face, by gently tapping them with a small iron bar. 
This gives them a yet greater resemblance to natural 
pearls, which are very seldom absolutely regular. 

No mention is made in ancient writers of artifi- 
cial pearls being made, and it is not till we come 
down to the beginning of the sixteenth century 
that we find Venice had then established a reputa- 
tion for this branch of industry. 

At first the glass balls were filled with various 
materials, generally with a base of mercury. But 
in the year 1680 a rosary-maker named Jacquin 
conceived the idea of using, in the place of this 
mercurial mixture, a harmless substance that pro- 
duced an infinitely more perfect colour. 

This substance, the essence of orient, is formed 



248 PRECIOUS STONES. 

from the scales of the bleak or ablette, a little white 
fish which abounds in the Seine, the Marne, and 
the Loiret 

The fishes are rubbed rather roughly in pure 
water, contained in a large basin ; the whole is then 
strained through a linen cloth, and left for several 
days to settle, when the water is drawn off. The 
sediment forms the essefice of orient. It requires 
from 17,000 to 18,000 fishes to obtain 500 grammes 
(a little over a pound) of this substance. 

The scaly substance is liable to decompose 
quickly, and numerous chemical agents are em- 
ployed by different manufacturers to preserve it. 
These means are kept a secret, but it is known 
that liquid ammonia, or the volatile alkali, is one 
of the substances most commonly used. 

The process of colouring the pearl is commenced 
by lining the interior of the ball with a delicate 
layer of perfectly limpid and colourless parchment- 
glue; and before it is quite dry, the essence of 
orient is introduced by means of a slender blow- 
pipe. It is then allowed to dry ; the pearl is filled 
with wax, and, if intended for a necklace, is pierced. 

FALSE CORAL. 

A number of objects are made at the present day 
of a composition intended to resemble coral, but 



ARTIFICIAL COLOURING. 249 

this imitation is by no means a success. It is a 
paste formed of marble dust and isinglass. The 
colour is given by a mixture of vermilion and 
minium incorporated with the mass. 

ARTIFICIAL COLOURING OF HARD STONES 
USED BY ENGRAVERS. 

The hard stones preferred by engravers are those 
which offer different tints or strongly-contrasted 
colours. As these vari-coloured stones are much 
more costly than stones of the same nature of a 
single colour, chemistry has been applied to for 
an artificial colouring; and the result is, that the 
greater part of hard stones engraved at the present 
day are artificially coloured. 

The stone to be coloured is steeped in oil, and 
notwithstanding its apparent impermeability, is 
easily penetrated by the liquid. After being soaked 
a certain time, it is taken out, and, however per- 
fectly it may be dried, a certain quantity of the oil 
always remains in its pores. It is then placed in 
a capsule, covered with sulphuric acid, and heated 
to boiling point : this heat is maintained until the 
sulphuric acid is evolved, when the stone is with- 
drawn and washed, and is found to have become 
black. 

If the stone is of a quite homogeneous texture, 



250 PRECIOUS STONES. 

the blackness will be uniform ; but if, as often hap- 
pens, its constitution is not very regular, the most 
porous parts absorb the greater quantity of oil, 
and varied effects of colouring are produced, which 
furnish to the artist the desirable opposition of tints. 

This operation can be easily explained. The oil 
being composed of the three elements — carbon, 
hydrogen, and oxygen, it follows that if the hydro- 
gen and oxygen are removed, carbon remains. It 
is precisely this removal that sulphuric acid effects. 
Penetrating in the track of the oil into the pores of 
the stone, it determines the union and elimination 
of the hydrogen and oxygen, and leaves carbon 
diffused throughout the stone in a state of excessive 
division. It is these minute particles of carbon 
that impart a definite colour to the stone. 

So far as regards the colouring, this process 
furnishes excellent results; but when it is asked. 
Should the prepared stone be considered equal to 
those coloured by nature .-• we must answer in the 
negative, notwithstanding the opinion generally 
held. 

No doubt, in ordinary conditions, the fixity of 
carbon is absolute, but in this case we must remem- 
ber that it is in a state of the most extreme divi- 
sion ; and seeing that the natural porosity of the 
stone is increased by the sulphuric acid, and that 
porosity is highly favourable to the combination of 



ARTIFICIAL COLOURING. 25 1 

bodies, it seems to be not impossible that in course 
of time the carbon may undergo a slow combustion, 
and the colour of the stone be more or less de- 
stroyed. 

It is impossible, too, that a substance so corro- 
sive as sulphuric acid should not make some im- 
pression on the stone. Silica, it is true, is not 
attacked by this liquid, but it is altered in a re- 
markable manner ; and then precious stones of the 
agate class are not formed exclusively of silica, 
but contain small quantities of different substances 
on which sulphuric acid has a very decided effect. 

The stones artificially coloured, then, may be 
used with great success for works of secondary 
value ; but they should never be employed by verit- 
able artists, who work " not for a day, but for all 
time." 



PART X. 

Cutting. Setting. Engraving of Precious Stones. 



" There is a fire 
And motion of the soul, which will not dwell 
In its own narrow being." 



As we have already shown in our first part, 
precious stones are sometimes amorphous and 
sometimes crystallized, but even in the latter case 
they are almost always masked or very imperfect ; 
and as much of their beauty, especially that of the 
diamond, depends upon what is called play of light, 
it is one of the first concerns of art to remove this 
mask and these imperfections. 

For every species of precious stone known to us 
there exists one form better suited than all others 
to show to advantage the effects of the light, which 
undergoes different modifications according to the 
peculiar molecular constitution of the stone on 
which it falls. 

The artistic series ot operations by which this 
desirable form is attained is called the cutting of 



DIAMOND-CUTTING. 253 

precious stones. That of the diamond is the most 
important. 

DIAMOND-CUTTING. 

The discovery of diamond-cutting has been very 
generally attributed to Louis de Berquem, a resi- 
dent of Bruges, in the year 1465 ; but in fact the 
actual discoveries of Berquem amounted only to the 
construction of a polishing-wheel, to be used with 
diamond-dust, and a systematic arrangement of the 
facets. 

Long before his time diamonds were cut in 
India and China; and the inventory of the jewels 
of Louis of Anjou, drawn up between 1360 and 
1368, included a number of cut diamonds. Indeed, 
150 years before the advent of Berquem diamond- 
cutters had existed in Paris, one of these especially, 
named Herman, had made notable progress in his 
art by the beginning of the fifteenth century. 

The grand centre of diamond-cutting in Ber- 
quem's time was the town of Bruges ; but pupils of 
his passed to Amsterdam, Antwerp, and Paris, 
where they established other workshops for dia- 
mond-cutting. Those at Paris did not at first 
succeed, but afterwards, under the patronage of 
Mazarin, diamond-cutting took an important posi- 
tion at Paris. After the death of Mazarin this 



254 PRECIOUS STONES. 

industry declined, and the revocation of the Edict 
of Nantes gave it a blow which it never recovered. 
At the present day Amsterdam is the head-quarters 
of this industry, and Mr. Coster's establishment in 
this city is the largest diamond-cutting establish- 
ment in the world. The art is still carried on at 
Paris, however, and also in London, and in both 
cities very successfully. 

Diamond-cutting has also been introduced into 
America, where it is carried on in the establishment 
of Mr. Morse at Boston, and more recently at New 
York, by the diamond company under the direction 
of Mr. Hermann. 

Diamonds are sometimes met with ia their natu- 
ral state in the form of well-defined crystals. It 
was no doubt these that first attracted men's 
attention, and for a long time they were the only 
ones to which any regard was paid. They are 
known as " native points." 

The primitive form of the crystallized diamond, 
the 'cube (Fig. 98), is extremely rare; it hardly 
occurs once among a thousand diamonds. 

The regular octahedron (Fig. 99) is a little more 
frequent. 

The dodecahedron, either regular (Fig. 100), or 
with curved edges (Fig. loi), is a frequent form; but 
the most common form of all is the octahedron, 
with a six-sided pyramid on each of its faces. 



;il|lllll|i|iiiiiii\''iiii 




DIAMOND-CUTTING. 



257 



As already mentioned, there is little doubt that 
the first diamonds to which value was attached 
were natural crystals, that is to say, octahedrons or 





Fig. 98. — Cubic System. 



Fig. 99. — Regular Octahedron. 



derived forms ; and when the cutting of diamonds 
became known in the Indies, it was necessarily dia- 
monds of this class that had to be operated upon. 




Figs. 100 and loi. — Common Forms of the Diamond. 

Accordingly, when we examine the figures of 

ancient Indian diamonds given by Tavernier and 

Bernier, we find that the primitive style of cutting 

in India was to take an octahedron, replace one of 

17 



258 PRECIOUS STONES. 

the points by a plane perpendicular to the axis, 
treat the opposite point in the same way, but so as 
to have a plane much smaller than the first, and 
then cut four bezels round the principal face. 

When the art of " splitting " became known, and 
it was possible by this process to obtain with ease 
flat-shaped diamonds of considerable size, the orien- 
tals took a fancy to stones of this kind, with their 




Fig. 102. — Flat Diamond of the Grand Mogul. 

four upper edges bevelled down exactly like the 
edges of ancient Venetian mirrors. Even at the 
present day this predilection has not disappeared, 
and similar stones are still those that are most 
highly prized by the inhabitants of India and Ara- 
bia. As an example of Indian cutting, we give a 
figure of a flat diamond that belonged to the Grand 
Mogul. 

There are two principal forms into which dia- 



DIAMOND-CUTTING." 259 

monds are cut, the brilliant and the rose, both of 
them subordinate, in the first place, to the thickness 
of the stone. To each of these two types is attached 
a number of derivative and more simple forms. 




Fig. 103. — Natural Octahedral Diamond. 

The starting point for the modern diamond, as 
for the ancient Indian form, is the simple octa- 




Fig. 104. Fig. 105. 

hedron. The following is the method employed in 
forming the octahedron into a brilliant: — 



26o 



PRECIOUS STONES. 



In Fig. 103 let the line AB which joins the two 
opposite summits, be divided into six equal parts, 
and let a plane perpendicular to the line AB pass 
through the second division from the upper point, 
and another plane also at right angles to AB pass 
through the first division from the lower point, 
then a small pyramid will be detached from each 
extremity, and there will remain the solid repre- 
sented by Fig. 104. 





Fig. 106. 



Fig. 107. 



These are the proportions in which the axis is 
cut by the French lapidaries, but English lapidaries 
usually cut five-eighteenths from the upper pyra- 
mid, and one-eighteenth from the lower. The 
upper and larger plane surface is called the table; 
the lower is named the collet (French, culasse). 

The four superior edges or ribs, and the four in- 
ferior edges, are then removed in such a way that 
the table and the collet are circumscribed by regular 
octagons, as represented by Fig. 105. 



DIAMOND-CUTTING. 26 1 

Lastly, the eight faces which hmit the table are 
cut each into four facets, forming the crown; and 
the eight faces of the collet are divided in the same 
manner to obtain the pavilion. 

The stone bears then sixty-four facets, besides 
thejiwo parallel planes — the table and the collet. 
It is called the double-cut, or recut brilliant, and 
being the style which best displays all the beauties 
of the diamond, it is used at the present day for all 
stones of fine water and of sufficient depth. Figs. 




Fig. io8. — Semi-brilliant. 

1 06 and 107 represent this form as seen both verti- 
cally and horizontally. 

The simple-cut brilhant has the same general 
form, but it has only eight facets above and eight 
below — sometimes only four — besides the table and 
collet. 

There is another cutting for stones whose thick- 
ness is small in proportion to their surface. It is 
the semi-brilliant. It consists of the upper part of a 
double-cut brilliant, cut off at the line of junction 
between the crown and pavilion. This form is 
represented by Fig. 108. 



262 



PRECIOUS STONES. 



THE ROSE. 

In rose-cutting, the diamond is flat underneath; 
the upper and convex part is covered with a vari- 
able number of facets, systematically disposed 
around a first, of which the summit occupies the 
centre of the stone. If the stone bears twenty-four 
facets it is a "Holland Rose;" if it has but eighteen 
or twenty, it is a "Semi-Holland;" if the number 
of facets is diminished to twelve, or eight, or even 
six, it is an "Antwerp Rose." 




Fig. 109. — Holland Rose. 

Sometimes rough diamonds, found in the form 
of pears, are covered with little facets, retaining 
the general form. These stones have the name of 
briolettes; they come exclusively from India, and are 
generally pierced in the upper part with a very 
small hole. No lapidary in Europe could drill 
such a hole in these diamonds. 

There are also known in commerce stones cut 



DIAMOND-CUTTING. 



263 



into pendeloques or pendants, in the form of a half- 
pear with table and collet, covered with facets on 
the collet side. They are very rare, and their 
price far exceeds that of brilliants of the same 
weight. Fig. no represents one of the pendeloques 
whi^ Tavernier saw in India, and which its pos- 
sessor would not part with for $11,160, 

Another special form of cutting is that which was 
employed for "the Sancy." Diamonds cut in this 




Fig. no. — Pendeloque of Tavernier. 

style have the form of flattened pears almost round, 
of a pendeloque shape, facetted both superiorly and 
inferiorly, and having a very small table above. 
M. Babinet thinks that this is the form in which 
both the Koh-i-noor and the Star of the South 
should have been cut. 

There is also the Star, invented by Caire, and 
but little used. It was designed in order to take 



264 PRECIOUS STONES. 

advantage of certain clear portions of rough dia- 
monds, which could not be otherwise used with- 
out great sacrifice of material. Fig. ill will show 
the appearance of stones cut in this manner. The 
form on the left represents the upper portion 
of the stone; the other two figures are alterna- 
tive forms in which the lower portion of the stone 
may be cut. 

The cutting of the diamond includes three series' 
of operations: the splitting or cleaving; the cutting, 




Fig. III. — The Star invented by Caire. 

properly so called; and the polishing. Special 
workmen are required for each one of these 
branches.^ 

It is to the splitter that the rough diamond is 
given; his quick penetration and ready action are 
to determine the future of the stone. 

First of all, he examines very carefully the little 

' The illustrations in this section relating to diamond-cutting are 
taken from fine water-colour drawings sent from Amsterdam and 
executed specially for this work. 




> ^s 



DIAMON D-CUTTING. 



267 



morsel in his hand; he decides how it should be 
shaped to retain the utmost weight with the most 
brilliant effect; he detects every flaw and streak, 




Fig. 113. — Details of a Compartment of the Splitter's Workroom. 

and he knows whether the imperfections are at 
the stone's surface or at its heart. Very quickly 
then he sets to work. He takes a longish wooden 
implement or baton, shaped so as to be con- 



268 



PRECIOUS STONES. 



veniently held in the hand, and having at one end 
a ferule extending a little beyond the wood and 
filled with a mastic or cement of resin and brick-dust, 
This cement he softens by heating it at a lamp, then 




Fig. 114.— The Splitter. 

embeds the diamond in it and lets the cement cool, 
by which means the diamond is firmly fixed in its 
place. With another diamond, sharply edged and 
secured in the same way, he cuts a notch in the 
diamond he is about to split. This notch is of a 
V shape, and must lie exactly in the direction of the 
cleavage-plane of the stone — a result which, though 



DIAMOND-CUTTING. 269 

apparently so difficult, is easily attained by the prac- 
tised eye and dexterous hand of the workman. A 
box beneath his work catches the dust, and a little 
sieve sifts at once the diamond-powder from the 
particles of resin dropped. 

When the notch is cut deep enough the workman 
places the wooden baton upright in a hole in a 
block of lead before him ; then introducing with one 
hand the blunt edge of a small steel ruler into the 
notch of the diamond, with the other he strikes the 
ruler a smart blow with a steel rod, and the stone 
is split. It is not without emotion that one sees 
this blow given, for the slightest error may prove 
fatal to the diamond's value for ever; but it is 
given without hesitation and with perfect com- 
posure. 

The stone, which is now divided into two parts, is 
removed from the cement; the main part undergoes 
a repetition of the operation until it has received its 
proper form and all flaws are removed ; and the 
fragments are carefully preserved to be cut into 
little roses, M^hich, however small, have a value. 

In Fig. 112 a general view is given of the room 
in which the splitters work in Coster's establishment 
at Amsterdam. Fig. 1 1 3 shows on a larger scale 
the complete arrangement of every division in this 
vast workroom. 

Fig. 115 is an illustration of the diamond-splitter's 



270 PRECIOUS STONES. 

table. The reader will see on the left the blunt- 
edged steel rulers and the iron rod, somewhat in 
the shape of a double cone, which serves as a ham- 
mer; on the right, a saucer containing diamonds, 
and supporting a pair of pincers, and a lamp; in front, 
a handle having the sharp-edged cutting diamond 




Fig. IIS.— Table of the Splitter. 

attached, and, standing upright, the wooden imple- 
ment which supports the diamond intended to be 
split; in the background is a globe of water for 
concentrating the light at such points as more par- 
ticularly require it. 

From the splitter the diamond passes to the 
cutter. 



DIAMOND-CUTTING. 



271 



At first sight the work appears to be exactly the 
same as at the table of the splitter. The cutter has 
two diamonds attached by cement to wooden 
handles, and the same sort of a box as the splitter 
has, to receive the diamond-dust. But the process 




is essentially different. Instead of cutting a notch 
in one of the diamonds, the cutter is slowly and 
laboriously grinding the two together in that 
mutual manner which accomplishes the smoothing 
of both stones. He is putting in practice the 
famous discovery which Louis de Berquem is falsely 
said to have made by chance, and, from the primi- 



2/2 PRECIOUS STONES. 

tive form received from the splitter, he is shaping 
the facets of the brilHant or the rose. 

The work requires great muscular force, and the 
hands of the cutters have to be supported by- 
gloves — we might almost call them cases — of stiff 
leather. These gloves are seen in Fig. 117, which 




Fig. 117. — Diamond-cutter's Table. 

represents the tools necessary to the work-table of 
the cutter. 

A diamond, in the hands of the cutter, has not yet 
become an object of beauty; it has no lustre or 
transparency, and is even more unpromising in 
aspect than the rough diamond. The adamantine 
lustre, which is one of its special beauties; its trans- 



DIAMOND-CUTTING. 273 

parency so pure; its refraction so powerful — all this 
is given to the diamond in the third phase of the 
cutting operation; and this phase belongs to the 
polisher. 

The work of the cutter is not confined to the re- 
moAfM of the outer crust of the stones — he gives 
them the definite form which they are to preserve. 
If the stone is thick enough to produce a brilliant, 
he forms first the table, then the collet, and suc- 
cessively all the facets of the pavilion and the 
crown. It is easily seen that in all this labour a 
great deal of latitude is left to the cutter; but, as 
the final weight, and consequently the value of the 
stone, depends in a great measure on his skill, it is 
only tried workmen that are intrusted with valu- 
able diamonds, such as those of larger size than 
four hundred to the carat. Smaller stones are 
made up in lots and delivered to the workmen 
after having been weighed. 

So long as the diamond-cutter is engaged on a 
piece of work he shuts up the stones every evening 
in a little iron coft'er provided with a padlock, of 
which he keeps the key. All these coffers, each 
with its number, are shut up after working hours in 
a large strong safe, and distributed to the work- 
men every morning. When the work is finished 
the large stones are weighed singly, the small 
stones in the lots, to see what the loss has been, 

18 



274 



PRECIOUS STONES. 



and, according to the extent of this, the payment is 
greater or less. If a stone is found to be wanting 
in any of the lots, the workman has to pay a fine 
much greater than the value of the stone. As a 




Fig. ii8. — General View of the Pollshing-room. 



brilliant of five hundred to the carat, or still more, 
a rose of a thousand to the carat, are very small 
objects, it often happens that they are lost in the 
course of the manipulations they have to pass 
through. The floor, and the dust upon it, are then 



DIAMOND-CUTTING. 2/5 

subjected to a most minute examination, in which 
a long silken broom is used. 

The polishing comprehends two distinct opera- 
tions — the setting, and the polishing properly so 
called. 

The setter has at his command a furnace filled 
with burning charcoal. His work is to solder the 
diamond into a quantity of alloy resting in a brass 
or copper cup, which has attached to it a rod for 
holding it by. The alloy consists of a mixture of 
tin and lead, which, when pressed into the cup, gives 
to the whole the form of an acorn, with the dia- 
mond as its apex. This soldering is no easy task. 
There are sixty-four distinct surfaces to be 
smoothed in the briUiant, and each of these must 
be properly adjusted in the burning mould. It 
would seem that the fingers of the setters are fire- 
proof, for it is with their fingers that they adjust the 
setting of the metal around the diamond; and when, 
after its manipulation, the alloy is plunged into 
water to be cooled, the cloud of steam that arises 
attests the painful temperature to which the hand 
of the workman has been subjected. 

The diamond, set as the apex of the acorn-shaped 
lump of metal, which again rests in a brazen cup 
with unyielding stem, is given to the polisher. 

The polishing-rooms are the most interesting 
apartments of the great establishments for diamond- 



2/6 



PRECIOUS STONES. 



cutting, such as that of Mr. Coster at Amsterdam. 
Before revolving steel disks, that are running 
scrupulously parallel with the floor, and turning 
noiselessly with a speed of two thousand revolutions 
to the minute, are numerous workmen intent upon 
their task. 




Fig. 119.— The Polisher. 



The eyes of these polishers seem of little use 
compared with their sense of touch, which has been 
exquisitely educated. It is by the instinct of their 
finger-ends that the point of the diamond — kept 
constantly wet with mingled diamond-dust and 
olive-oil — is adjusted with determinate exactness of 



DIAMOND-CUTTING. 



277 



position, to the face of the revolving disk. It is 
clamped in a wooden rest, and the pressure is regu- 
lated by leaden weights, so that the diamond just 
touches the flying wheel. To the casual observer 




Fig. T20. — Instruments used in Polishing. 



the polishing art seems to be one requiring little 
skill or intelligence, but to acquire proficiency in 
the work requires years of assiduous toil. 

From generation to generation the trade has 
been carried on, and the patient and monotonous 
toil and technical skill inherited and acquired by 



2/8 PRECIOUS STONES. 

the finished workman is sure to be rewarded at 
last by a ghttering surface from the hardest stone. 

Sometimes months, and even years, are required 
for the perfecting of single stones. African diamonds 
are said to be particularly hard and difficult to 
polish ; but, in the end, the most hopelessly resis- 
tant gem yields to the indefatigability of man. 

In Fig. 120 are shown some of the objects con- 
.nected with the polishing of diamonds. In the 
background towards the left the polishing wheel of 
steel is seen, and scattered over the table three of 
the copper cups, filled with alloy. The implement 
near the centre of the table, with the two upright 
pieces or feet at the left end of it, is for holding the 
diamond on the wheel during the operation of 
polishing. For this purpose it has a kind of vice at 
the end, in which the tail or stem of the copper cup 
is tightly screwed, and the whole then forms a 
sort of tripod, the cup which carries the diamond 
forming the third foot. The nut of the screw, 
and the key for turning it, are seen at the head of 
the implement. Its use will be understood from 
the cut showing the polisher at work (Fig. 1 19). 

CUTTING OF PRECIOUS STONES OTHER THAN 
THE DIAMOND. 

All the other precious stones are less hard than 



CUTTING OF PRECIOUS STONES. 279 

the diamond, and they display besides the greatest 
difference from each other in this respect. Accord- 
ingly, though the processes followed in cutting them 
are not very dissimilar outwardly to those by which 
the diamond is cut and polished, yet the materials 
mg^e use of are very different. The wheels have the 
same form and are set up in the same way, but 
they are made of much softer materials, and the 
powders with which they are covered are much less 
hard than diamond-dust. 

Disks of lead, tin, or sometimes zinc, copper, and 
hard wood, are what the ordinary lapidaries use, and 
instead of diamond-dust they employ emery (a sub- 
stance consisting chiefly of alumina), tripoli or rotten- 
stone (silica), tin-putty (bioxide of tin), and English 
red (anhydrous peroxide of iron). Different wheels 
and polishing substances are used according to the 
kind of stone. The greater part of colourless 
precious stones are cut with the leaden wheel, and 
with rotten-stone well moistened. This serves to 
give the first polish to all precious stones in which 
silica is the principal element — agates, jaspers, hya- 
cinths, &c. 

The two styles most employed are the step-cut 
and the smooth-cut or cabochon. When the latter 
is very flat it is called the "tallow-drop." Each of 
these may be round or oval, elongated or square. 

The cabochon is plane, convex or concave on its 



280 



PRECIOUS STONES. 



inferior side. In the latter case it is the double 
cjibochon. 

Concave cabochons are employed for stones mo- 
derately transparent, and this disposition tends to 
facilitate a more easy transmission of light Gar- 
nets of a certain size are often cut in this form; and 
this cutting is used especially for the adularia, the 
cat's-eye, the hydrophane, and, above all, the opal. 




Kig. 121. — Cutting of Precious Stones other than the Diamond. 

It serves better than any other form to display the 
special beauties of these different stones. 

The stones cut in step or pavilion form are 
generally not very thick, and there are usually more 
steps or degrees on the lower than the upper side; 
as on the upper part a large table in the centre is 
generally reserved. Figs. 121 and 122 represent 
forms given to a great number of coloured stones, 
especially the emerald and the oriental aquamarine. 

There are other forms, in which the stones cut 
in circles or ovals have a large table on the upper 
surface, surrounded with facets, which are either 



MOUNTING OF PRECIOUS STONES. 28 1 

triangular or triangular and quadrangular both. In 
this case the lower face is covered with quadrilateral 
facets, and has a very small table in the centre. 




Fig. 122. — Forms in which Stones are often cut. 

Rubies and sapphires are frequently cut very 
much like the diamond, with this difference, that 
there is less thickness given to their upper part. 

MOUNTING OF PRECIOUS STONES. 

Precious stones, which enter into jewelry in a 
thousand ways, are rarely seen simply pierced and 
suspended as a drop; on the contrary, they are 
nearly always elaborately mounted in silver or 
gold. At the present day gold is used almost 
exclusively for the setting both of colourless and 
coloured stones; but silver is considered more artistic 
for the former, as it preserves their limpidity and 
brilliancy, and even lends them additional splen- 
dour, as gold does to the coloured stones. 



282 PRECIOUS STONES. 

There are two modes of mounting precious 
stones — one, which leaves only the upper part 
visible, called the close-setting; and the other, 
leaving the stone uncovered both above and below, 
called the open-setting. 

A modification of the open-setting, called the 
knife-edge setting, leaving the edge of the stone 
clear, is used with beautiful effect for diamonds. 

ENGRAVING OF PRECIOUS STONES.. 

When we examine the marvellous artistic pro- 
ductions, executed in cameo or intaglio, upon pre- 
cious stones, we naturally think that the means 
employed must be numerous and complicated, but 
in reality the apparatus and the tools of the en- 
graver are as simple as those of the lapidary. They 
consist of the lathe, and a series of little rods with 
heads of different shapes, all of which can be ad- 
justed to the lathe. 

The lathe, as will be seen from the appended 
figure, is a very simple affair. The axis, driven by 
the belt from the wheel, is pierced at the centre 
with an orifice, into which the tools for cutting the 
stone are firmly fixed by means of a screw. The 
engraver wets the extremity of the mounted rod 
with diamond-dust made into a paste with olive- 
oil, and as the wheel is in motion he applies the 



ENGRAVING OF PRECIOUS STONES. 



283 



stone, properly prepared by the lapidary, and firmly 
cemented to a piece of reed, to the revolving tool. 
The diamond-dust enables the tool to cut into the 




Fig. 123. — The Lathe at work. 



stone with ease. As the design is frequently very 
elaborate and of the greatest delicacy, the tools are 
necessarily multiform. 

Among the different varieties there are four most 



284 PRECIOUS STONES. 

used. The first is hollow; it describes circles with 
the utmost facility, and serves, when required, to 
perforate hard stones. The second is a disk quite 
blunt at the edge. The third is a sharp-edged disk 
of very frequent use, serving as a saw. ' The fourth 
is a rod, terminated by a little sphere, and is very 
frequently used. Fig. 124 shows all the tools used 
by the engraver. 

As precious stones suitable for engraving have 
always a considerable and sometimes a very high 
value, it is important to be able to make use of every 
portion of them. They are therefore sawn instead 
of being ground down, so that the portion removed 
may also be made use of This operation may be 
performed in different ways. The most ancient and 
simple method consists in fixing the stone to the 
extremity of a support, and cutting it by the friction 
of a bow, strung with two iron wires twisted together, 
and impregnated with diamond-dust. This method, 
however, is both tedious and irregular, and hence 
instruments, infinitely more rapid and precise, have 
been substituted for the bow. 

Fig. 125 represents the mill of the lapidary, with 
the polishing disk replaced by a steel disk with a 
cutting edge, against which the workman applies the 
stone with his left hand, while he sets the apparatus 
in motion with his right. The disk is sprinkled 
with diamond-dust, which the workman collects 



L f=) 





ENGRAVING OF PRECIOUS STONES. 



287 



and keeps always supplied to the edges of the 
wheel. This work is usually performed by the 
lapidary, preparatory to the engraver's task; indeed, 
the stone is sometimes set by the jeweller before it 




Fig. 125. — ^Apparatus for Sawing Hard Stones. 



is engraved, in which case it is embedded in cork. 
If it is merely shaped and not set, it is fastened 
upon a baton with lapidary's cement. 

The tools and apparatus employed by the en- 
graver are therefore very simple; but just as the 



288 PRECIOUS STONES. 

sculptor, besides his chisel and block of marble, 
must have a certain amount of technical skill, and, 
above all, the artistic faculty, so is it with the en- 
graver in hard stones. 

To execute a high-class work of art on a stone 
of one colour is very difficult; but stones of different 
colours, and with the colours variously disposed, 
are those most commonly employed. Here the 
difficulty is enormously increased, for the artist, 
besides having to attend to the cutting, properly so 
called, has also to compose his design, and to 
observe that in working it out he takes the fullest 
advantage of the different colours of the stone. 

We shall give one example to show the wonder- 
ful effects that are sometimes obtained by artists 
when working on stones of different colours. The 
design is that of a shepherd sitting on a rock with 
a staff in his hand. His face, hands, and legs are 
flesh colour; his coat has several holes in it through 
which his shirt appears ; and the artist has taken 
advantage of a wood-coloured vein in the stone to 
represent his staff. Beside him is a tree with some 
green leaves on it, and having the trunk designed 
with the utmost fidelity. 

Stones on which the design is raised above the 
general surface are called cameos; those having the 
design sunk below the surface are called intaglios. 

The stones used for cameo-cutting are generally 



ENGRAVING OF PRECIOUS STONES. 289 

opaque or semi-transparent, such as the onyx, sar- 
donyx, cornehan, agate, &c. They are suited for 
subjects of the most varied character. 

Intaglios are very pften executed in transparent 
stones, and the subjects treated in this manner are 
more Hmited in number. They are chiefly such as 
seals, devices, coats of arms, &c. 

In modern times Rome has almost a monopoly of 
this class of productions, exporting every year more 
than $50,000 worth of them. 

In the Paris Exhibition of 1867 several magni- 
ficent cameos by Girometti were exhibited. One 
of these was a grand composition, representing 
Ptolemy Philadelphus and Arsinoe, valued at $6000, 
and executed on a superb oriental cornelian, which 
alone cost $2000. 

Another design was an Achilles, on an oriental 
sardonyx, and valued at $2400. This was a striking 
example of the skilful manner in which artists may 
avail themselves of the different tints of a stone. 
The face of the hero seems bronzed by the sun, 
while his helmet and shield are of the colour of 
steel. 

19 



290 



PRECIOUS STONES. 



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